The present invention relates to the field of wireless handheld devices, and generally to wireless portable devices which require the transmission and reception of electromagnetic wave signals.
Wireless handheld or portable devices typically operate one or more cellular communication standards and/or wireless connectivity standards, each standard being allocated in one or more frequency bands, and said frequency bands being contained within one or more regions of the electromagnetic spectrum.
For that purpose, a space within the wireless handheld or portable device is usually dedicated to the integration of a radiating system. The radiating system is, however, expected to be small in order to occupy as little space as possible within the device, which then allows for smaller devices, or for the addition of more specific equipment and functionality into the device. At the same time, it is sometimes required for the radiating system to be flat since this allows for slim devices or in particular, for devices which have two parts that can be shifted or twisted against each other.
Many of the demands for wireless handheld or portable devices also translate to specific demands for the radiating systems thereof.
A typical wireless handheld device must include a radiating system capable of operating in one or more frequency regions with good radioelectric performance (such as for example in terms of input impedance level, impedance bandwidth, gain, efficiency, or radiation pattern). Moreover, the integration of the radiating system within the wireless handheld device must be correct to ensure that the wireless device itself attains a good radioelectric performance (such as for example in terms of radiated power, received power, or sensitivity).
This is even more critical in the case in which the wireless handheld device is a multifunctional wireless device. Commonly-owned patent U.S. Pat. No. 8,738,103 and patent publication WO2008/009391 and describe a multifunctional wireless device. The entire disclosure of said patent publication numbers WO2008/009391 and U.S. Pat. No. 8738103 are hereby incorporated by reference.
For a good wireless connection, high gain and efficiency are further required. Other more common design demands for radiating systems are the voltage standing wave ratio (VSWR) and the impedance which is supposed to be about 50 ohms.
Other demands for radiating systems for wireless handheld or portable devices are low cost and a low specific absorption rate (SAR).
Furthermore, a radiating system has to be integrated into a device or in other words a wireless handheld or portable device has to be constructed such that an appropriate radiating system may be integrated therein which puts additional constraints by consideration of the mechanical fit, the electrical fit and the assembly fit.
Of further importance, usually, is the robustness of the radiating system which means that the radiating system does not change its properties upon smaller shocks to the device.
A radiating system for a wireless device typically includes a radiating structure comprising an antenna element which operates in combination with a ground plane layer providing a determined radioelectric performance in one or more frequency regions of the electromagnetic spectrum. This is illustrated in
Although the radiating structure is usually very efficient at the resonance frequency of the antenna element and maintains a similar performance within a frequency range defined around said resonance frequency (or resonance frequencies), outside said frequency range the efficiency and other relevant antenna parameters deteriorate with an increasing distance to said resonance frequency.
Furthermore, the radiating structure operating at a resonance frequency of the antenna element is typically very sensitive to external effects (such as for instance the presence of plastic or dielectric covers that surround the wireless device), to components of the wireless device (such as for instance, but not limited to, a speaker, a microphone, a connector, a display, a shield can, a vibrating module, a battery, or an electronic module or subsystem) placed either in the vicinity of, or even underneath, the antenna element, and/or to the presence of the user of the wireless device.
Any of the above mentioned aspects may alter the current distribution and/or the electromagnetic field distribution of a radiation mode of the antenna element, which usually translates into detuning effects, degradation of the radioelectric performance of the radiating structure and/or the radioelectric performance wireless device, and/or greater interaction with the user (such as an increased level of SAR).
A further problem associated to the integration of the radiating structure, and in particular to the integration of the antenna element, in a wireless device is that the volume dedicated for such an integration has continuously shrunk with the appearance of new smaller and/or thinner form factors for wireless devices, and with the increasing convergence of different functionality in a same wireless device.
Some techniques to miniaturize and/or optimize the multiband behavior of an antenna element have been described in the prior art. However, the radiating structures therein described still rely on exciting a radiation mode on the antenna element.
For example, commonly-owned patent U.S. Pat. No. 7,554,490 describes a new family of antennas based on the geometry of space-filling curves. Also, commonly-owned patent U.S. Pat. No. 7,528,782 relates to a new family of antennas, referred to as multilevel antennas, formed by an electromagnetic grouping of similar geometrical elements. The entire disclosures of the aforesaid patent numbers U.S. Pat. No. 7,554,490 and U.S. Pat. No. 7,528,782 are hereby incorporated by reference.
Some other attempts have focused on antenna elements not requiring a complex geometry while still providing some degree of miniaturization by using an antenna element that is not resonant in the one or more frequency ranges of operation of the wireless device.
For example, WO2007/128340 discloses a wireless portable device comprising a non-resonant antenna element for receiving broadcast signals (such as, for instance, DVB-H, DMB, T-DMB or FM). The wireless portable device further comprises a ground plane layer that is used in combination with said antenna element. Although the antenna element has a first resonance frequency above the frequency range of operation of the wireless device, the antenna element is still the main responsible for the radiation process and for the electromagnetic performance of the wireless device. This is clear from the fact that no radiation mode can be excited on the ground plane layer because the ground plane layer is electrically short at the frequencies of operation (i.e., its dimensions are much smaller than the wavelength).
With such limitations, while the performance of the wireless portable device may be sufficient for reception of electromagnetic wave signals (such as those of a broadcast service), the antenna element could not provide an adequate performance (for example, in terms of input return losses or gain) for a cellular communication standard requiring also the transmission of electromagnetic wave signals.
Commonly-owned patent publication WO2008/119699 and US2010/0109955 describe a wireless handheld or portable device comprising a radiating system capable of operating in two frequency regions. The radiating system comprises an antenna element having a resonance frequency outside said two frequency regions, and a ground plane layer. In this wireless device, while the ground plane layer contributes to enhance the electromagnetic performance of the radiating system in the two frequency regions of operation, it is still necessary to excite a radiation mode on the antenna element. In fact, the radiating system relies on the relationship between a resonance frequency of the antenna element and a resonance frequency of the ground plane layer in order for the radiating system to operate properly in said two frequency regions.
The entire disclosure of the aforesaid patent publication number WO2008/119699 and US2010/0109955 are hereby incorporated by reference.
Some further techniques to enhance the behavior of an antenna element relate to optimizing the geometry of a ground plane layer associated to said antenna element. For example, commonly-owned patent U.S. Pat. No. 7,688,276 describes a new family of ground plane layers based on the geometry of multilevel structures and/or space-filling curves. The entire disclosure of the aforesaid patent U.S. Pat. No. 7,688,276 is hereby incorporated by reference.
Another limitation of current wireless handheld or portable devices relates to the fact that the design and integration of an antenna element for a radiating structure in a wireless device is typically customized for each device. Different form factors or platforms, or a different distribution of the functional blocks of the device will force to redesign the antenna element and its integration inside the device almost from scratch.
For at least the above reasons, wireless device manufacturers regard the volume dedicated to the integration of the radiating structure, and in particular the antenna element, as being a toll to pay in order to provide wireless capabilities to the handheld or portable device.
Therefore, a wireless device not requiring an antenna element would be advantageous as it would case the integration of the radiating structure into the wireless handheld or portable device. The volume freed up by the absence of the antenna element would enable smaller and/or thinner devices, or even to adopt radically new form factors which are not feasible today due to the presence of an antenna element. Furthermore, by eliminating precisely the element that requires customization, a standard solution is obtained which only requires minor adjustments to be implemented in different wireless devices.
A wireless handheld or portable device that does not require of an antenna element, yet the wireless device featuring an adequate radioelectric performance would be an advantageous solution. This problem is solved by an antennaless wireless handheld or portable device according to the present invention.
It is an object of the present invention to provide a wireless handheld or portable device (such as for instance but not limited to a mobile phone, a smartphone, a PDA, an MP3 player, a headset, a USB dongle, a laptop computer, a gaming device, a digital camera, a PCMCIA or Cardbus 32 card, or generally a multifunction wireless device) which does not require an antenna element for the transmission and reception of electromagnetic wave signals. Such an antennaless wireless device is yet capable of operation in one or more frequency regions of the electromagnetic spectrum with enhanced radioelectric performance, increased robustness to external effects and neighboring components of the wireless device, and/or reduced interaction with the user.
Another object of the invention relates to a method to enable the operation of a wireless handheld or portable device in one or more frequency regions of the electromagnetic spectrum with enhanced radioelectric performance, increased robustness to external effects and neighboring components of the wireless device, and/or reduced interaction with the user, without requiring the use of an antenna element.
An antennaless wireless handheld or portable device according to the present invention operates one, two, three, four or more cellular communication standards (such as for example GSM 850, GSM 900, GSM 1800, GSM 1900, UMTS, HSDPA, CDMA, W-CDMA, LTE, CDMA2000, TD-SCDMA, etc.), wireless connectivity standards (such as for instance WiFi, IEEE802.11 standards, Bluetooth, ZigBee, UWB, WiMAX, WiBro, or other high-speed standards), and/or broadcasts standards (such as for instance FM, DAB, XDARS, SDARS, DVB-H, DMB, T-DMB, or other related digital or analog video and/or audio standards), each standard being allocated in one or more frequency bands, and said frequency bands being contained within one, two, three or more frequency regions of the electromagnetic spectrum.
In the context of this document, a frequency band preferably refers to a range of frequencies used by a particular cellular communication standard, a wireless connectivity standard or a broadcast standard; while a frequency region preferably refers to a continuum of frequencies of the electromagnetic spectrum. For example, the GSM 1800 standard is allocated in a frequency band from 1710 MHz to 1880 MHz while the GSM 1900 standard is allocated in a frequency band from 1850 MHz to 1990 MHz. A wireless device operating the GSM 1800 and the GSM 1900 standards must have a radiating system capable of operating in a frequency region from 1710 MHz to 1990 MHz.
The antennaless wireless handheld or portable device according to the present invention may have a candy-bar shape, which means that its configuration is given by a single body. It may also have a two-body configuration such as a clamshell, flip-type, swivel-type or slider structure. In some other cases, the device may have a configuration comprising three or more bodies. It may further or additionally have a twist configuration in which a body portion (e.g. with a screen) can be twisted (i.e., rotated around two or more axes of rotation which are preferably not parallel).
For a wireless handheld or portable device which is slim and/or whose configuration comprises two or more bodies, the requirements on maximum height of the antenna element are very stringent, as the maximum thickness of each of the two or more bodies of the device may be limited to 5, 6, 7, 8 or 9 mm. The technology disclosed herein makes it possible for a wireless handheld or portable device to feature an enhanced radioelectric performance without requiring an antenna element, thus solving the space constraint problems associated to such devices.
In the context of the present document a wireless handheld or portable device is considered to be slim if it has a thickness of less than 14 mm, 13 mm, 12 mm, 11 mm, 10 mm, 9 mm or 8 mm.
According to the present invention, an antennaless wireless handheld or portable device advantageously comprises at least five functional blocks: a user interface module, a processing module, a memory module, a communication module and a power management module. The user interface module comprises a display, such as a high resolution LCD, OLED or equivalent, and is an energy consuming module, most of the energy drain coming typically from the backlight use. The user interface module may also comprise a keypad and/or a touchscreen, and/or an embedded stylus pen. The processing module, that is a microprocessor or a CPU, and the associated memory module are also major sources of power consumption. The fourth module responsible of energy consumption is the communication module, an essential part of which is the radiating system. The power management module of the antennaless wireless handheld or portable device includes a source of energy (such as for instance, but not limited to, a battery or a fuel cell) and a power management circuit that manages the energy of the device.
In accordance with the present invention, the communication module of the antennaless wireless handheld or portable device includes a radiating system capable of transmitting and receiving electromagnetic wave signals in a first frequency region. Said radiating system comprises a radiating structure comprising at least one ground plane layer including a connection point, at least one radiation booster including a connection point and an internal port. The internal port is defined between the connection point of the at least one radiation booster and the connection point of the at least one ground plane layer. The radiating system further comprises a radiofrequency system, and an external port.
In some cases, the radiating system of an antennaless wireless handheld or portable device comprises a radiating structure consisting of at least one ground plane layer including a connection point, at least one radiation booster including a connection point and an internal port.
The radiofrequency system comprises a first port connected to the internal port of the radiating structure and a second port connected to the external port of the radiating system. Said radiofrequency system modifies the impedance of the radiating structure, providing impedance matching to the radiating system in the at least the first frequency region of operation of the radiating system.
In this text, a port of the radiating structure is referred to as an internal port; while a port of the radiating system is referred to as an external port. In this context, the terms “internal” and “external” when referring to a port are used simply to distinguish a port of the radiating structure from a port of the radiating system, and carry no implication as to whether a port is accessible from the outside or not.
An aspect of the present invention relates to the use of the ground plane layer of the radiating structure as an efficient radiator to provide an enhanced radioelectric performance in one or more frequency regions of operation of the wireless handheld or portable device, eliminating thus the need for an antenna element. A radiation mode of the ground plane layer can be advantageously excited when a dimension of said ground plane layer is on the order of, or even larger than, one half of the wavelength corresponding to a frequency of operation of the radiating system.
Therefore, in an antennaless wireless device according to the present invention, no other parts or elements of the wireless handheld or portable device have significant contribution to the radiation process.
In some embodiments, said radiation mode occurs at a frequency advantageously located above (i.e., at a frequency higher than) the first frequency region of operation of the wireless handheld or portable device. In some other embodiments, the frequency of said radiation mode is within said first frequency region.
A ground plane rectangle is defined as being the minimum-sized rectangle that encompasses a ground plane layer of the radiating structure. That is, the ground plane rectangle is a rectangle whose sides are tangent to at least one point of said ground plane layer.
In some cases, the ratio between a side of the ground plane rectangle, preferably a long side of the ground plane rectangle, and the free-space wavelength corresponding to the lowest frequency of the first frequency region is advantageously larger than a minimum ratio. Some possible minimum ratios are 0.1, 0.16, 0.2, 0.3, 0.4, 0.5, 0.6, 0.8, 1, 1.2 and 1.4. Said ratio may additionally be smaller than a maximum ratio (i.e., said ratio may be larger than a minimum ratio but smaller than a maximum ratio). Some possible maximum ratios are 0.4, 0.5, 0.6, 0.8, 1, 1.2. 1.4, 1.6, 2, 3, 4, 5, 6, 8 and 10.
Setting a dimension of the ground plane rectangle, preferably the dimension of its long side, relative to the wavelength within these ranges makes it possible for the ground plane layer to support an efficient radiation mode, in which the currents flowing on the ground plane layer are substantially aligned and contribute in phase to the radiation process.
The gain of a radiating structure depends on factors such as its directivity, its radiating efficiency and its input return loss. Both the radiating efficiency and the input return loss of the radiating structure are frequency dependent (even directivity is strictly frequency dependent). A radiating structure is usually very efficient around the frequency of a radiation mode excited in the ground plane layer and maintains a similar radioelectric performance within the frequency range defined by its impedance bandwidth around said frequency. Since the dimensions of the ground plane layer (or those of the ground plane rectangle) are comparable to, or larger than, the wavelength at the frequencies of operation of the wireless device, said radiation mode may be efficient over a broad range of frequencies.
In this text, the expression impedance bandwidth is to be interpreted as referring to a frequency region over which a wireless handheld or portable device and a radiating system comply with certain specifications, depending on the service for which the wireless device is adapted. For example, for a device adapted to transmit and receive signals of cellular communication standards, a radiating system having a relative impedance bandwidth of at least 5% (and more preferably not less than 8%, 10%, 15% or 20%) together with an efficiency of not less than 30% (advantageously not less than 40%, more advantageously not less than 50%) can be preferred. Also, an input return-loss of −3 dB or better within the corresponding frequency region can be preferred.
A wireless handheld or portable device generally comprises one, two, three or more multilayer printed circuit boards (PCBs) on which to carry the electronics. In a preferred embodiment of an antennaless wireless handheld or portable device, the ground plane layer of the radiating structure is at least partially, or completely, contained in at least one of the layers of a multilayer PCB.
In some cases, a wireless handheld or portable device may comprise two, three, four or more ground plane layers. For example a clamshell, flip-type, swivel-type or slider-type wireless device may advantageously comprise two PCBs, each including a ground plane layer.
The at least one radiation booster couples the electromagnetic energy from the radiofrequency system to the ground plane layer in transmission, and from the ground plane layer to the radiofrequency system in reception. Thereby the radiation booster boosts the radiation or reception of electromagnetic radiation.
In some examples, the at least one radiation booster has a maximum size smaller than 1/30, 1/40, 1/50, 1/60, 1/80, 1/100, 1/140 or even 1/180 times the free-space wavelength corresponding to the lowest frequency of the first frequency region of operation of the antennaless wireless handheld or portable device.
In the prior art in general an antenna element is said to be small (or miniature) when it can be fitted in a small space compared to a given operating wavelength. More precisely, a radiansphere is usually taken as the reference for classifying whether an antenna element is small. The radiansphere is an imaginary sphere having a radius equal to said operating wavelength divided by two times π. Therefore, a maximum size of the antenna element must necessarily be not larger than the diameter of said radiansphere (i.e., approximately equal to ⅓ of the free-space operating wavelength) in order to be considered small at said given operating wavelength.
As established theoretically by H. Wheeler and L. J. Chu in the mid 1940's, small antenna elements typically have a high quality factor (Q) which means that most of the power delivered to the antenna element is stored in the vicinity of the antenna element in the form of reactive energy rather than being radiated into space. In other words, an antenna element having a maximum size smaller than ⅓ of the free-space operating wavelength may be regarded as radiating poorly by a skilled-in-the-art person.
The at least one radiation booster for a radiating structure according to the present invention has a maximum size at least smaller than 1/30 of the free-space wavelength corresponding to the lowest frequency of the first frequency region of operation. That is, said radiation booster fits in an imaginary sphere having a diameter ten (10) times smaller than the diameter of a radiansphere at said same operating wavelength.
Setting the dimensions of the radiation booster to such small values is advantageous because the radiation booster substantially behaves as a non-radiating element for all the frequencies of the first frequency region, thus substantially reducing the loss of energy into free space due to undesired radiation effects of the radiation booster, and consequently enhancing the transfer of energy between the radiation booster and the ground plane layer. Therefore, the skilled-in-the-art person could not possibly regard the radiation booster as being an antenna element.
Said maximum size is preferably defined by the largest dimension of a booster box that completely encloses said radiation booster, and in which the radiation booster is inscribed.
More specifically, a booster box for a radiation booster is defined as being the minimum-sized parallelepiped of square or rectangular faces that completely encloses the radiation booster and wherein each one of the faces of said minimum-sized parallelepiped is tangent to at least a point of said radiation booster. Moreover, each possible pair of faces of said minimum-size parallelepiped sharing an edge forms an inner angle of 90°.
In some examples, one of the dimensions of a booster box can be substantially smaller than any of the other two dimensions, or even be close to zero. In such cases, said booster box collapses to a practically two-dimensional entity. The term dimension preferably refers to an edge between two faces of said parallelepiped.
Additionally, in some of these examples the at least one radiation booster has a maximum size larger than 1/1400, 1/700, 1/350, 1/250, 1/180, 1/140 or 1/120 times the free-space wavelength corresponding to the lowest frequency of said first frequency region. Therefore, in some examples the at least one radiation booster has a maximum size advantageously smaller than a first fraction of the free-space wavelength corresponding to the lowest frequency of the first frequency region but larger than a second fraction of said free-space wavelength.
Setting the dimensions of the radiation booster to be above some certain minimum value is advantageous to obtain a higher level of the real part of the input impedance of the radiating structure (measured at the internal port of the radiating structure when disconnected from the radiofrequency system) and hence enhance the transfer of energy between the radiation booster and the ground plane layer.
In some other cases, preferably in combination with the above feature of an upper bound for the maximum size of the radiation booster although not always required, to reduce even further the losses in the radiation booster due to residual radiation effects, the radiation booster is designed so that the radiating structure has a first resonance frequency (as measured at the internal port of said radiating structure when disconnected from the radiofrequency system) at a frequency much higher than the frequencies of the first frequency region of operation. In some examples, the radiation booster connected to said internal port has a dimension substantially close to a quarter of the wavelength corresponding to said first resonance frequency. In some examples, the ratio between the first resonance frequency of the radiating structure at its internal port when disconnected from the radiofrequency system and the highest frequency of said first frequency region is preferably larger than a certain minimum ratio. Some possible minimum ratios are 3.0, 3.4, 3.8, 4.0, 4.2, 4.4, 4.6, 4.8, 5.0, 5.2, 5.4, 5.6, 5.8, 6.0, 6.2, 6.6 or 7.0.
In the context of this document, a resonance frequency of the radiating structure preferably refers to a frequency at which the input impedance of said radiating structure (as measured at its internal port when disconnected from the radiofrequency system) has an imaginary part equal to zero.
With such a small radiation booster, and with the radiating structure including said radiation booster operating in a frequency range much lower than said first resonance frequency, the input impedance of the radiating structure (measured at its internal port when the radiofrequency system is disconnected) features an important reactive component (either capacitive or inductive) within the range of frequencies of the first frequency region of operation. That is, the input impedance of the radiating structure at said internal port when disconnected from the radiofrequency system has an imaginary part not equal to zero for any frequency of the first frequency region.
In some examples the radiation booster is substantially planar defining a two-dimensional structure, while in other cases the radiation booster is a three-dimensional structure that occupies a volume. In particular, in some examples, the smallest dimension of a booster box is not smaller than a 70%, an 80% or even a 90% of the largest dimension of said booster box, defining a volumetric geometry. Radiation boosters having a volumetric geometry may be advantageous to enhance the radioelectric performance of the radiating structure, particularly in those cases in which the maximum size of the radiation booster is very small relative to the free-space wavelength corresponding to the lowest frequency of the first frequency region.
Moreover, providing a radiation booster with a volumetric geometry can be advantageous to reduce the other two dimensions of its radiator box, leading to a very compact solution. Therefore, in some examples in which the radiation booster has a volumetric geometry, it is preferred to set a ratio between the first resonance frequency of the radiating structure at its internal port when disconnected from the radiofrequency system and the highest frequency of the first frequency region above 4.8, or even above 5.4.
In a preferred embodiment, the radiation booster comprises a conductive part. In some cases said conductive part may take the form of, for instance but not limited to, a conducting strip comprising one or more segments, a polygonal shape (including for instance triangles, squares, rectangles, hexagons, or even circles or ellipses as limit cases of polygons with a large number of edges), a polyhedral shape comprising a plurality of faces (including also cylinders or spheres as limit cases of polyhedrons with a large number of faces), or a combination thereof.
In some examples, the conductive part of a radiation booster may be a contacting means of a circuit component, such as for example a pin, a soldering ball, or a soldering pad of an integrated circuit package, or of a surface-mount technology (SMT) electronic component.
In some examples, the connection point of a radiation booster is advantageously located substantially close to an end, or to a corner, of said conductive part.
In some examples, the conductive part is connected to the ground plane layer, while in other examples said conductive part is not connected to the ground plane layer. Connecting the conductive part of the radiation booster to the ground plane layer lowers effectively the real part of the input impedance of the radiating structure at its internal port when disconnected from the radiofrequency system, controlling thus the energy transfer between the radiation booster and the ground plane layer.
In another preferred example, the radiation booster comprises a gap (i.e., absence of conducting material) defined in the ground plane layer. Said gap is delimited by one or more segments defining a curve. The connection point of the radiation booster is located at a first point along said curve. The connection point of the ground plane layer is located at a second point along said curve, said second point being different from said first point.
In an example, said gap intersects the perimeter of the ground plane layer. That is, the curve defined by the one or more segments delimiting said gap is open. In another example, said gap does not intersect the perimeter of the ground plane layer (i.e., the curve defined by the one or more segments delimiting said gap is closed).
In a preferred example of the present invention, a major portion of the at least one radiation booster (such as at least a 50%, or a 60%, or a 70%, or an 80% of the surface of said radiation booster) is placed on one or more planes substantially parallel to the ground plane layer. In the context of this document, two surfaces are considered to be substantially parallel if the smallest angle between a first line normal to one of the two surfaces and a second line normal to the other of the two surfaces is not larger than 30°, and preferably not larger than 20°, or even more preferably not larger than 10°.
In some examples, said one or more planes substantially parallel to the ground plane layer and containing a major portion of a radiation booster of the radiating structure are preferably at a height with respect to said ground plane layer not larger than a 2% of the free-space wavelength corresponding to the lowest frequency of the first frequency region of operation of the radiating system. In some cases, said height is smaller than 7 mm, preferably smaller than 5 mm, and more preferably smaller than 3 mm.
In some embodiments, the at least one radiation booster is substantially coplanar to the ground plane layer. Furthermore, in some cases the at least one radiation booster is advantageously embedded in the same PCB as the one containing the ground plane layer, which results in a radiating structure having a very low profile.
In a preferred example the radiating structure is arranged within the wireless handheld or portable device in such a manner that there is no ground plane in the orthogonal projection of a radiation booster onto the plane containing the ground plane layer. In some examples there is some overlapping between the projection of a radiation booster and the ground plane layer. In some embodiments less than a 10%, a 20%, a 30%, a 40%, a 50%, a 60% or even a 70% of the area of the projection of a radiation booster overlaps the ground plane layer. Yet in some other examples, the projection of a radiation booster onto the ground plane layer completely overlaps the ground plane layer.
In some cases it is advantageous to protrude at least a portion of the orthogonal projection of a radiation booster beyond the ground plane layer, or alternatively remove ground plane from at least a portion of the projection of a radiation booster, in order to adjust the levels of impedance and to enhance the impedance bandwidth of the radiating structure. This aspect is particularly suitable for those examples when the volume for the integration of the radiating structure has a small height, as it is the case in particular for slim wireless handheld or portable devices.
In some examples, a radiation booster is preferably located substantially close to an edge of the ground plane layer, preferably said edge being in common with a side of the ground plane rectangle. In some examples, a radiation booster is more preferably located substantially close to an end of said edge or to the middle point of said edge.
In some embodiments said edge is preferably an edge of a substantially rectangular or elongated ground plane layer.
In an example, the radiation booster is located preferably substantially close to a short edge of the ground plane rectangle, and more preferably substantially close to an end of said short edge or to the middle point of said short edge. Such a placement for the radiation booster with respect to the ground plane layer is particularly advantageous when the radiating structure features at its internal port, when the radiofrequency system is disconnected, an input impedance having a capacitive component for the frequencies of the first frequency region of operation.
In another example, the radiation booster is located preferably substantially close to a long edge of the ground plane rectangle, and more preferably substantially close to an end of said long edge or to the middle point of said long edge. Such a placement for the radiation booster is particularly advantageous when the radiating structure features at its internal port, when the radiofrequency system is disconnected, an input impedance having an inductive component for the frequencies of said first frequency region.
In some other examples, a radiation booster is advantageously located substantially close to a corner of the ground plane layer, preferably said corner being in common with a corner of the ground plane rectangle.
In the context of this document, two points are substantially close to each other if the distance between them is less than 5% (more preferably less than 3%, 2%, 1% or 0.5%) of the lowest frequency of operation of the radiating system. In the same way, two linear dimensions are substantially close to each other if they differ in less than 5% (more preferably less than 3%, 2%, 1% or 0.5%) of said lowest frequency of operation.
In some examples, the connection point of the ground plane layer is located advantageously close to the connection point of the radiation booster in order to facilitate the interconnection of the radiofrequency system with the radiating structure. Therefore, those locations specified above as being preferred for the placement of the radiation booster are also advantageous for the location of the connection point of the ground plane layer. Therefore, in some examples said connection point is located substantially close to an edge of the ground plane layer, preferably an edge in common with a side of the ground plane rectangle, or substantially close to a corner of the ground plane layer, preferably said corner being in common with a corner of the ground plane rectangle. Such an election of the position of the connection point of the ground plane layer may be advantageous to provide a longer path to the electrical currents flowing on the ground plane layer, lowering the frequency of the radiation mode of the ground plane layer.
In some embodiments, the radiofrequency system comprises a matching network that transforms the input impedance of the radiating structure, providing impedance matching to the radiating system in at least the first frequency region of operation of the radiating system.
Said matching network can comprise a single stage or a plurality of stages. In some examples, the matching network comprises at least two, at least three, at least four, at least five, at least six, at least seven, at least eight or more stages.
A stage comprises one or more circuit components (such as for example but not limited to inductors, capacitors, resistors, jumpers, short-circuits, switches, delay lines, resonators, or other reactive or resistive components). In some cases, a stage has a substantially inductive behavior in the first frequency region of operation of the radiating system, while another stage has a substantially capacitive behavior in said first frequency region, and yet a third one may have a substantially resistive behavior in said first frequency region.
A stage can be connected in series or in parallel to other stages and/or to at least one port of the radiofrequency system.
In some examples, the matching network alternates stages connected in series (i.e., cascaded) with stages connected in parallel (i.e., shunted), forming a ladder structure. In some cases, a matching network comprising two stages forms an L-shaped structure (i.e., series-parallel or parallel-series). In some other cases, a matching network comprising three stages forms either a pi-shaped structure (i.e., parallel-series-parallel) or a T-shaped structure (i.e., series-parallel-series).
In some examples, the matching network alternates stages having a substantially inductive behavior, with stages having a substantially capacitive behavior.
In an example, a stage may substantially behave as a resonant circuit (such as, for instance, a parallel LC resonant circuit or a series LC resonant circuit) in the first frequency region of operation of the radiating system. The use of stages having a resonant circuit behavior allows one part of the matching network be effectively connected to another part of said matching network for a given range of frequencies, and be effectively disabled for another range of frequencies.
In an example, the matching network comprises at least one active circuit component (such as for instance, but not limited to, a transistor, a diode, a MEMS device, a relay, or an amplifier) in at least one stage.
In some embodiments, the matching network preferably includes a reactance cancellation circuit comprising one or more stages, with one of said one or more stages being connected to the first port of the radiofrequency system.
In the context of this document, reactance cancellation preferably refers to compensating the imaginary part of the input impedance at the internal port of the radiating structure when disconnected from the radiofrequency system so that the input impedance of the radiating system at its external port has an imaginary part substantially close to zero for a frequency preferably within the first frequency region. In some less preferred examples, said frequency may also be higher than the highest frequency of the first frequency region (although preferably not higher than 1.1. 1.2. 1.3 or 1.4 times said highest frequency) or lower than the lowest frequency of the first frequency region (although preferably not lower than 0.9, 0.8 or 0.7 times said lowest frequency). Moreover, the imaginary part of an impedance is considered to be substantially close to zero if it is not larger (in absolute value) than 15 Ohms, and preferably not larger than 10 Ohms, and more preferably not larger than 5 Ohms.
In a preferred embodiment, the radiating structure features at its internal port when the radiofrequency system is disconnected an input impedance having a capacitive component for the frequencies of the first frequency region of operation. In that embodiment, the reactance cancellation circuit comprises a first stage having a substantially inductive behavior for all the frequencies of the first frequency region of operation of the radiating system. More preferably, said first stage comprises an inductor. In some cases, said inductor may be a lumped inductor. Said first stage is advantageously connected in series with the first port of the radiofrequency system, said first port being connected to the internal port of the radiating structure of a radiating system.
In another preferred embodiment, the radiating structure features at its internal port when the radiofrequency system is disconnected an input impedance having an inductive component for the frequencies of the first frequency region of operation. In that embodiment, the reactance cancellation circuit comprises a first stage and a second stage forming an L-shaped structure, with said first stage being connected in parallel and said second stage being connected in series. Each of the first and the second stage has a substantially capacitive behavior for all the frequencies of the first frequency region of operation of the radiating system. More preferably, said first stage and said second stage comprise each a capacitor. In some cases, said capacitor may be a lumped capacitor. Said first stage is advantageously connected in parallel with the first port of the radiofrequency system, while said second stage is connected to said first stage.
In some embodiments, the matching network may further comprise a broadband matching circuit, said broadband matching circuit being preferably connected in cascade to the reactance cancellation circuit. With a broadband matching circuit, the impedance bandwidth of the radiating structure may be advantageously increased. This may be particularly interesting for those cases in which the relative bandwidth of the first frequency region is large.
In a preferred embodiment, the broadband matching circuit comprises a stage that substantially behaves as a resonant circuit (preferably as a parallel LC resonant circuit or as a series LC resonant circuit) in the first frequency region of operation of the radiating system.
In some examples, the matching network may further comprise in addition to the reactance cancellation circuit and/or the broadband matching circuit, a fine tuning circuit (also called third tuning circuit) to correct small deviations of the input impedance of the radiating system with respect to some given target specifications.
In a preferred example, the reactance cancellation circuit is connected to the first port of the radiofrequency system (i.e., the port connected to the internal port of the radiating structure) and the fine tuning circuit is connected to the second port of the radiofrequency system (i.e., the port connected to the external port of the radiating system). In an example, then the broadband matching circuit is operationally connected in cascade between the reactance cancellation circuit and the fine tuning circuit. In another example, the matching network does not comprise a broadband matching circuit and the reactance cancellation circuit is connected in cascade directly to the fine tuning circuit.
In some examples, at least some circuit components in the stages of the matching network are discrete lumped components (such as for instance SMT components), while in some other examples all the circuit components of the matching network are discrete lumped components. In some examples, at least some circuit components in the stages of the matching network are distributed components (such as for instance a transmission line printed or embedded in a PCB containing the ground plane layer of the radiating structure), while in some other examples all the circuit components of the matching network are distributed components.
In some examples, at least some, or even all, circuit components in the stages of the matching network may be integrated into an integrated circuit, such as for instance a CMOS integrated circuit or a hybrid integrated circuit.
In some embodiments, the radiofrequency system may comprise a frequency selective element such as a diplexer or a bank of filters to separate the electrical signals of different frequencies.
In some embodiments, the radiofrequency system includes two, three, four or more matching networks and a switching matrix. The switching matrix allows selecting which one of the two or more matching networks is operationally connected to a port of the radiofrequency system. In these embodiments, the radiofrequency system further comprises a control circuit to select which matching network is selected at any given time, hence providing reconfiguration capabilities to the radiofrequency system.
In some preferred embodiments, the switching matrix is advantageously connected to the first port of the radiofrequency system (i.e., the port connected to internal port of the radiating structure).
Moreover, in a more preferred embodiment the radiofrequency system comprises a second switching matrix, said second switching matrix being connected to the second port of the radiofrequency system (i.e., the port connected to external port of the radiating system).
A radiating system comprising such a reconfigurable radiofrequency system may be advantageous to adapt the radiating system to different working environments, or to different modes of operation of the wireless device. It may also allow re-using a same radiating system for different frequency regions that are not used simultaneously. For example a same cellular communication standard may be allocated in different frequency regions of the electromagnetic spectrum depending on the geographical region. An antennaless wireless handheld or portable device may advantageously select the matching network optimized for instance to the frequency region corresponding to a European standard, to an American standard, or to an Asian standard depending on where the wireless device is being used at any given moment.
In some examples, one, two, three or even all the stages of the matching network may contribute to more than one functionality of said matching network. A given stage may for instance contribute to two or more of the following functionalities from the group comprising: reactance cancellation, impedance transformation (preferably, transformation of the real part of said impedance), broadband matching and fine tuning matching. In other words, a same stage of the matching network may advantageously belong to two or three of the following circuits: reactance cancellation circuit, broadband matching circuit and fine tuning circuit. Using a same stage of the matching network for several purposes may be advantageous in reducing the number of stages and/or circuit components required for the matching network of a radiofrequency system, reducing the real estate requirements on the PCB of the antennaless wireless handheld or portable device in which the radiating system is integrated.
In other examples, each stage of the matching network serves only to one functionality within the matching network. Such a choice may be preferred when low-end circuit components, having for instance a worse tolerance behavior, a more pronounced thermal dependence, and/or a lower quality factor, are used to implement said matching network.
In some examples, the radiating system is capable of operating in at least two, three, four, five or more frequency regions of the electromagnetic spectrum, said frequency regions allowing the allocation of two, three, four, five, six or more frequency bands used in one or more standards of cellular communications, wireless connectivity and/or broadcast services.
In some examples, a frequency region of operation (such as for example the first frequency region) of a radiating system is preferably one of the following: 824-960 MHZ, 1710-2170 MHz, 2.4-2.5 GHZ, 3.4-3.6 GHZ, 4.9-5.875 GHZ, or 3.1-10.6 GHZ.
In some embodiments, the radiating structure comprises two, three, four or more radiation boosters, each of said radiation boosters including a connection point, and each of said connection points defining, together with a connection point of the ground plane layer, an internal port of the radiating structure. Therefore, in some embodiments the radiating structure comprises two, three, four or more radiation boosters, and correspondingly two, three, four or more internal ports. In such embodiments, the radiofrequency system comprises additional ports to be connected to some, or even all, internal ports of the radiating structure.
In some examples, a same connection point of the ground plane layer is used to define at least two, or even all, internal ports of the radiating structure.
In some examples, the radiating system comprises a second external port and the radiofrequency system comprises an additional port, said additional port being connected to said second external port. That is, the radiating system features two external ports.
In some embodiments the radiating structure comprises a plastic or dielectric carrier (such as for instance made of Poly Carbonate, Liquid Crystal Polymer, Poly Oxide Methylene, PC-ABS, or PVC) that provides mechanical support to the at least one radiation booster of said radiating structure. In other cases, the at least one radiation booster is affixed to a plastic cover of the wireless handheld or portable device.
In some embodiments a radiation booster may be advantageously arranged in an integrated circuit package (i.e., a package having a form factor for integrated circuit packages).
In some embodiments, said integrated circuit package advantageously comprises a semiconductor chip or die arranged inside the package. Moreover, the radiation booster is preferably arranged in the package but not in said semiconductor die or chip.
In some cases, the integrated circuit package has a form factor selected from the list comprising: single-in-line (SIL) package, dual-in-line (DIL) package, dual-in-line with surface mount technology (DIL-SMT) package, quad-flat-package (QFP) package, quad-flat-no-lead (QFN) package, pin grid array (PGA) package, ball grid array (BGA) package, plastic ball grid array (PBGA) package, ceramic ball grid array (CBGA) package, tape ball grid array (TBGA) package, super ball grid array (SBGA) package, micro ball grid array (μBGA) package, small outline package and leadframe package. Moreover, in some examples, any of these form factors may be used in its CSP (Chip Scale Package) version, wherein the semiconductor chip or die typically fills up to an 85% of the package area.
The integrated circuit package further comprises at least one terminal (such as for instance but not limited to a pad, a pin or a lead) or, more preferably, a plurality of terminals.
In some preferred examples, the contact point of the radiation booster is connected to a terminal of the integrated circuit package. Moreover, in these examples the radiofrequency system is at least in part not included in the integrated circuit package. Having at least a part of the radiofrequency system outside the integrated circuit package may offer to the user greater flexibility in the customization of the matching network and the selection of particular circuit components to obtain a desired radioelectric performance of the radiating system.
In some cases according to the present invention, a terminal of the integrated circuit package may constitute the conductive part of the radiation booster.
In some examples, the connection point of the ground plane layer of the radiating structure is connected to at least one terminal of the integrated circuit package. In these examples, the integrated circuit package includes at least part of the radiofrequency system. Having at least part of the radiofrequency system inside the integrated circuit may enable the use of for instance active circuit components, or have an adaptive matching network which can be reconfigured to different working environments and conditions. In these cases, the radiofrequency system may advantageously further comprise a control circuit, preferably included in the semiconductor chip or die, to configure such an adaptive matching network.
Embodiments of the invention are shown in the enclosed figures. Herein shows:
Further characteristics and advantages of the invention will become apparent in view of the detailed description of some preferred embodiments which follows. Said detailed description of some preferred embodiments of the invention is given for purposes of illustration only and in no way is meant as a definition of the limits of the invention, made with reference to the accompanying figures.
Referring now to
In
In particular, in
Referring now to
The radiating structure 400 comprises a radiation booster 401 and a ground plane layer 402. In
The ground plane rectangle 450 has a long side of approximately 100 mm and a short side of approximately 40 mm. Therefore, in accordance with an aspect of the present invention, the ratio between the long side of the ground plane rectangle 450 and the free-space wavelength corresponding to the lowest frequency of the first frequency region (i.e., 824 MHZ) is advantageously larger than 0.2. Moreover, said ratio is advantageously also smaller than 1.0.
In this example, the radiation booster 401 includes a conductive part featuring a polyhedral shape comprising six faces. Moreover, in this case said six faces are substantially square having an edge length of approximately 5 mm, which means that said conductive part is a cube. In this case, the conductive part of the radiation booster 401 is not connected to the ground plane layer 402. A booster box 451 for the radiation booster 401 coincides with the external area of said radiation booster 401. In
In accordance with an aspect of the present invention, a maximum size of the radiation booster 401 (said maximum size being a largest edge of the booster box 451) is advantageously smaller than 1/50 times the free-space wavelength corresponding to the lowest frequency of the first frequency region of operation of the radiating structure 400. In particular, said maximum size is also advantageously larger than 1/180 times said free-space wavelength.
In
In the radiating structure 400, the radiation booster 401 protrudes beyond the ground plane layer 402. That is, the radiation booster 401 is arranged with respect to the ground plane layer 402 in such a manner that there is no ground plane in the orthogonal projection of the radiation booster 401 onto the plane containing the ground plane layer 402. The radiation booster 401 is located substantially close to an edge of the ground plane layer 402, in particular to a short edge of the substantially rectangular ground plane layer 402 and, more precisely, the radiation booster 401 is located substantially close to a corner of said ground plane layer 402.
The radiation booster 401 comprises a connection point 403 located on the lower right corner of the bottom face of the radiation booster 401. In turn, the ground plane layer 402 also comprises a connection point 404 substantially on the upper right corner of the ground plane layer 402. An internal port of the radiating structure 400 is defined between connection point 403 and connection point 404.
The very small dimensions of the radiation booster 401 result in said radiating structure 400 having a first resonance frequency at a frequency much higher than the frequencies of the first frequency region. In this case, the ratio between the first resonance frequency of the radiating structure 400 measured at its internal port (in absence of a radiofrequency system connected to it) and the highest frequency of the first frequency region is advantageously larger than 4.2.
With such small dimensions of the radiation booster 401, the input impedance of the radiating structure 400 measured at the internal port features an important reactive component, and in particular a capacitive component, within the frequencies of the first frequency region.
This can be observed in
Curve 600 is located on the lower half of the Smith chart, which indeed indicates that said input impedance has a capacitive component (i.e., the imaginary part of the input impedance has a negative value) for all frequencies of the first frequency range (i.e., between point 601 and point 602).
A radiofrequency system 500 comprises a first port 501 to be connected to the internal port of the radiating structure 400, and a second port 502 to be connected to the external port of the radiating system. In this example, the radiofrequency system 500 further comprises a matching network including a reactance cancellation circuit 507 and a broadband matching circuit 508.
The reactance cancellation circuit 507 includes one stage comprising one single circuit component 504 arranged in series and featuring a substantially inductive behavior in the first frequency region. In this particular example, the circuit component 504 is a lumped inductor. The inductive behavior of the reactance cancellation circuit 507 advantageously compensates the capacitive component of the input impedance of the radiating structure 400.
Such an effect can be observed in
The broadband matching circuit 508 includes also one stage and is connected in cascade with the reactance cancellation circuit 507. Said stage of the broadband matching circuit 508 comprises two circuit components: a first circuit component 505 is a lumped inductor and a second circuit component 506 is a lumped capacitor. Together, the circuit components 505 and 506 form a parallel LC resonant circuit (i.e., said stage of the broadband matching circuit 508 behaves substantially as a resonant circuit in the first frequency region of operation).
Comparing
Alternatively, the effect of the radiofrequency system of
Another preferred embodiment of a radiating structure according to the present invention is disclosed in
The radiating structure 800 is very similar to the radiating structure 400 already discussed in connection with
However, the placement of the radiation booster 801 with respect to the ground plane layer 802 is different from what it was shown in
Despite the radiation booster 801 being located above the ground plane layer 802, said radiation booster 801 is not connected to said ground plane layer 802. An internal port of the radiating structure 800 is defined between a connection point of the radiation booster 801 and a connection point of the ground plane layer 802.
Referring now to
The reactance cancellation circuit 910 is connected to the first port 901 and the fine tuning circuit 912 is connected to the second port 902. The broadband matching circuit 911 is operationally connected between the reactance cancellation circuit 910 and the fine tuning circuit 912, so that said three circuits are connected in cascade.
The input impedance of the radiating structure 800 measured at its internal port (in absence of the radiofrequency system 900) has an imaginary part featuring an important capacitive component. In
The broadband matching circuit 911 is similar to the one used for the radiofrequency system 500, and includes one stage substantially behaving as an LC parallel resonant circuit comprising an inductor 904 and a capacitor 905 connected in parallel.
The fine tuning circuit 912 adds two more stages to the matching network of the radiofrequency system 900. Said two stages form an L-shaped structure having a series inductor 906 and a parallel capacitor 907. In this particular example, the fine tuning circuit 912 provides an additional transformation of the impedance, necessary to attain the required level of impedance matching in the first frequency region.
The same typical results are shown in
The radiating structure 1200 comprises a radiation booster 2000 and a ground plane layer 2010, having a substantially rectangular shape. In
In this example, the radiation booster 2000 comprises a gap defined in the ground plane layer 2010. A closer view of said radiation booster 2000 is provided in
In this example said gap intersects the perimeter of the ground plane layer, which means that the curve delimiting said gap is open. As it can be seen in
The use of the radiation booster 2000 in the radiation structure 1200 results in a advantageously planar solution, simplifying its integration in a wireless handheld or portable device. In this example, a booster box 1251 for the radiation booster 2000 is substantially planar (i.e., one of its dimensions is substantially close to zero). Furthermore, since the gap of the radiation booster 2000 has a substantially square shape, the booster box 1251 contains the segments 2001, 2002 and 2003.
In accordance with an aspect of the present invention, a maximum size of the radiation booster 2000 (said maximum size being a largest edge of the booster box 1251) is advantageously smaller than 1/40 times the free-space wavelength corresponding to the lowest frequency of the first frequency region of operation of radiating structure 1200. Additionally, in this example said maximum size is also advantageously larger than 1/250 times said free-space wavelength.
With such small dimensions of the radiation booster 2000, the radiating structure 1200 features a first resonance frequency at a frequency much higher than the frequencies of the first frequency region and, in consequence, the input impedance of the radiating structure 1200 measured at its internal port (in absence of a radiofrequency system connected to it) has an important reactive component, in particular an inductive component, within the frequencies of said first frequency region. In this case, the ratio between the first resonance frequency of the radiating structure 1200 measured at its internal port (in absence of a radiofrequency system connected to it) and the highest frequency of the first frequency region is advantageously larger than 5.0.
In the radiating structure 1200, the radiation booster 2000 is located with respect to the ground plane layer 2010 in such a manner that the gap of the radiation booster 2000 intersects an edge of the ground plane layer 2010, in particular a long edge of a substantially rectangular ground plane layer 2010. More precisely, the radiation booster 2000 is located substantially close to the middle point of said long edge.
The input impedance of the radiating structure 1200 measured at its internal port (in absence of the radiofrequency system 1300) has an imaginary part featuring a significant inductive component, as it can be seen in
The reactance cancellation circuit 1310 is connected to the first port 1301 and comprises two stages having a substantially capacitive behavior and forming an L-shaped structure with a parallel capacitor 1303 and a series capacitor 1304. The capacitive behavior of the reactance cancellation circuit 1310 advantageously compensates the inductive component of the input impedance of the radiating structure 1200, transforming curve 1400 (
The broadband matching circuit 1311 is connected in cascade after the reactance cancellation circuit 1310 and is similar in topology to the ones already discussed in connection with
The broadband matching circuit 1311 further transforms the input impedance of the antenna structure and converts curve 1420 into curve 1440, said curve 1440 being the input impedance that would be observed at the second port 1302 if the fine tuning circuit 1312 were removed and said second port 1302 were directly connected to a port 1321. Curve 1440 features a compact loop that unfortunately is shifted towards the upper half of the Smith chart. If said loop were centered on the center of the Smith chart, impedance matching would be obtained over a much broader range of frequencies.
Finally, the fine tuning circuit 1312 is connected in cascade between the broadband matching circuit 1311 and the second port 1302, and includes one stage having a substantially capacitive behavior for all frequencies of the first frequency region. In particular said stage comprises a series circuit element (lumped capacitor 1307). The fine tuning circuit 1312 provides the additional transformation of the input impedance necessary to re-center the loop of curve 1440 on the center of the Smith chart. In
Referring now to
In this particular example, two of the faces of the radiation booster (namely, the top face 1601 and the bottom face 1602) are substantially parallel to the ground plane layer 1610, which may facilitate the integration of the radiation booster 1600 into a wireless handheld or portable device by mounting said radiation booster 1600 on a PCB of the wireless device, and in particular the PCB that also comprises the ground plane layer 1610. However, in other examples, the radiation booster 1600 may not be substantially parallel to the ground plane layer 1610.
In this case, a booster box associated to said radiation booster 1600 coincides with the external surface of the radiation booster 1600. Since the smallest dimension of said booster box is not smaller than the 90% of the largest dimension of said booster box, the radiation booster 1600 takes full advantage of being a three-dimensional structure that occupies a volume.
The radiation booster 1600 also comprises a connection point 1603 advantageously located substantially close to a corner of the radiation booster 1600, said corner being in particular also a corner of the bottom face 1602. Said connection point 1603 defines together with a connection point of the ground plane layer 1611 an internal port of a radiating structure.
As in the example of
The radiation booster 1630 further comprises a connection point 1631, located substantially close to a corner of the radiation booster 1630, which defines together with the connection point of the ground plane layer 1611 an internal port of a radiating structure.
In
Said conductive part further comprises a conductive strip 1662 having a substantially elongated shape and featuring two ends: A first end of the conductive strip 1662 is connected to the conductive polygonal shape 1661; and a second end of the conductive strip 1662 includes a connection point 1663, which together with the connection point of the ground plane layer 1611 defines an internal port of a radiating structure. In this example, the conductive strip 1662 is arranged substantially perpendicular to the ground plane layer 1610.
A radiating structure resulting from the combination of any of the radiation boosters 1600, 1630, 1660 in
Referring now to
In particular,
Finally,
Although
Referring now to
In this example, said conductive part of the radiation booster 1800 is connected to the ground plane layer 1810. For that purpose, a second end of the third conductive strip 1803 is connected to the ground plane layer 1810.
The radiation booster comprises a connection point 1804 located on a second end of the first conductive strip 1801, said connection point 1804 defining together with a connection point of the ground plane layer 1811 an internal port of a radiating structure 1820. Such a radiation booster 1800 may be advantageous when it is desired to have a radiating structure that features an input impedance at the internal port 1820 (in absence of a radiofrequency system) having a positive imaginary part for all the frequencies of the first frequency region (i.e., said imaginary part being an inductive component).
In
Another possible placement of the radiation booster 1800 is as indicated in the radiating structure 1960 shown in
Conductive strip 1891 includes a connection point that together with a connection point of the ground plane layer 1810 defines an internal port of the radiating structure 1895. Conductive strip 1893 is connected to the ground plane layer 1810. Conductive strip 1892 connects conductive strip 1891 with conductive strip 1893.
As it can be observed, the radiation booster 1890 protrudes beyond the short edge of the ground plane layer 1902, so that there is no ground plane in the projection of said radiation booster 1890 on the plane containing the ground plane layer 1810. Moreover, the radiation booster 1890 is advantageously located on a corner of the ground plane layer 1810 (in particular, the corner defined by the intersection of the long edge 1901 and the short edge 1902) and the conductive strip 1893 is closer to said corner than it is the conductive strip 1891.
Although
In
The radiation booster 2050 comprises a connection point 2055 located at a first point along the curve delimiting said gap. In particular said connection point 2055 is located on a point of segment 2053. The ground plane layer 2010 also includes a connection point 2011, said connection point 2011 being located at a second point along said curve, and more precisely on a point of segment 2051. Although not always required, the connection point of the radiation booster 2055 and the connection point of the ground plane layer 2011 are advantageously located on segments at opposite sides of said gap of the radiation booster 2050 (segment 2053 and segment 2051 respectively).
Of course,
In
Referring now to
A further example is depicted in
The radiation booster 2301 comprises a connection point 2306 located at a first point along said curve, said first point being at an end of the conductive strip 2304. The ground plane layer 2302 also comprises a connection point 2307 located at a second point along said curve delimiting the inner gap 2303, and in particular said second point being substantially close to an end of segment 2310.
In these examples, the radiation boosters 2201, 2301, 2401 are arranged with respect to the ground plane layer 2202, 2302, 2402 in such a manner that said radiation boosters 2201, 2301, 2401 are located substantially close to a long edge of the ground plane layer 2202, 2302, 2402, and in particular substantially centered with respect to said long edge. Such an arrangement is particularly advantageous when the input impedance of a radiating structure an has an inductive component. However, other placements for the radiation boosters 2201, 2301, 2401 are also possible.
Moreover, a connection point of these radiation boosters 2201, 2301, 2401 is preferably located on a point of a first segment of the curve delimiting the gap of said radiation boosters 2201, 2301, 2401, said first segment intersecting the perimeter of the ground plane layer 2202, 2302, 2402. Likewise, a connection point of the ground plane layer is preferably located on a point of a second segment of said curve, said second segment being opposite to said first segment and said second segment also intersecting the perimeter of the ground plane layer 2202, 2302, 2402.
These radiating structures 2200, 2300, 2400 feature an input impedance (measured at their internal port when disconnected from a radiofrequency system) having an imaginary part with an inductive component. Therefore, such radiating structures could be advantageously interconnected with a radiofrequency system such as the one shown in
A further radiating structure is depicted in
Referring now to
The switching matrix 2604 is connected between said first port 2601 and the first and second matching networks 2605, 2606 and allows selecting which one of the first and second matching networks 2605. 2606 is operationally connected to the first port 2601. The radiofrequency system 2600 also includes a control circuit 2607 that acts on the switching matrix 2604 to select which one of the first and second matching networks 2605, 2606 is selected at any given time.
In this example, the radiofrequency system 2600 comprises a second port 2602 and a third port 2603 connected to the first matching network 2605 and to the second matching network 2606 respectively.
An alternative example is presented in
A control circuit 2707 included in the radiofrequency system 2700 acts on the first and second switching matrices 2704, 2708 to select which one of the first and second matching networks 2705, 2706 is operationally connected to the first port 2701 and the second port 2702.
Although the radiofrequency systems 2600, 2700 have been described as comprising two matching networks, other possible radiofrequency systems according to the present invention could include three, four or more matching networks selectable by one or more switching matrices.
Number | Date | Country | Kind |
---|---|---|---|
08161722.7 | Aug 2008 | EP | regional |
08172925.3 | Dec 2008 | EP | regional |
P200930444 | Jul 2009 | ES | national |
P200930499 | Jul 2009 | ES | national |
This application is a continuation of U.S. patent application Ser. No. 18/083,071 filed Dec. 16, 2022, which is a continuation of U.S. patent application Ser. No. 17/479,703 filed Sep. 20, 2021, now U.S. Pat. No. 11,557,827, which is a continuation of U.S. patent application Ser. No. 16/827,048 filed Mar. 23, 2020, now U.S. Pat. No. 11,139,574, which is a continuation of U.S. patent application Ser. No. 15/973,124 filed May 7, 2018, now U.S. Pat. No. 10,734,724, which is a divisional of U.S. patent application Ser. No. 15/670,872 filed Aug. 7, 2017, now abandoned, which is a continuation of U.S. patent application Ser. No. 15/004,151, filed Jan. 22, 2016, now U.S. Pat. No. 9,761,944, which is a continuation of U.S. patent application Ser. No. 14/738,115 filed Jun. 12, 2015, now U.S. Pat. No. 9,276,307, which is a continuation of U.S. patent application Ser. No. 13/476,503 filed May 21, 2012, now U.S. Pat. No. 9,130,259, which is a continuation of U.S. patent application Ser. No. 12/669,147 filed Jan. 14, 2010, now U.S. Pat. No. 8,203,492, which is a 371 national phase of International application No. PCT/EP2009/005579, filed Jul. 31, 2009, which claims the benefit of U.S. Provisional Application No. 61/142,523, filed on Jan. 5, 2009, and also claims the benefit of U.S. Provisional Application No. 61/086,838, filed on Aug. 7, 2008, the entire contents of which are hereby incorporated by reference.
Number | Date | Country | |
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61142523 | Jan 2009 | US | |
61086838 | Aug 2008 | US |
Number | Date | Country | |
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Parent | 15670872 | Aug 2017 | US |
Child | 15973124 | US |
Number | Date | Country | |
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Parent | 18083071 | Dec 2022 | US |
Child | 18506652 | US | |
Parent | 17479703 | Sep 2021 | US |
Child | 18083071 | US | |
Parent | 16827048 | Mar 2020 | US |
Child | 17479703 | US | |
Parent | 15973124 | May 2018 | US |
Child | 16827048 | US | |
Parent | 15004151 | Jan 2016 | US |
Child | 15670872 | US | |
Parent | 14738115 | Jun 2015 | US |
Child | 15004151 | US | |
Parent | 13476503 | May 2012 | US |
Child | 14738115 | US | |
Parent | 12669147 | Jan 2010 | US |
Child | 13476503 | US |