This disclosure relates generally to antennas, and in particular to wideband polarization diverse antennas.
Wireless communication systems have historically undergone a revolution about once in every decade. Presently, 5th Generation (5G) wireless technology is out of its exploratory research phase, and the first wave of commercialization of 5G is being experienced, with its widespread adaptation anticipated by 2025. One of the benefits of 5G includes a much higher system capacity (100 to 1000 times more) than the current 4G systems. One of the approaches in achieving this several orders of magnitude increase in system capacity will be to exploit large quantities of new system bandwidth. This is prompting the migration towards higher frequencies, particularly in the millimeter-wave (“mmWave”) region of the spectrum which will release a large amount of bandwidth available to achieve higher capacity. The mmWave spectrum is the band of spectrum between 30 GHz and 300 GHz. Worldwide various standards organizations such as the international telecommunication union (ITU), the Federal Communications Commission (FCC) in the US, and the Ministry of Industry and Information Technology (MIIT) in China have already announced several mmWave bands for 5G systems.
In addition to moving to mmWave frequencies, another way to achieve increased system capacity is to use MIMO (multiple input multiple output) techniques. In MIMO, antenna diversity is used on either side of the communication link to create multiple spatial channels between the transmitter and the receiver. In short, large operating bandwidths and MIMO techniques are believed to be important enablers for future wireless communication systems of 5G and beyond.
The present invention is illustrated by way of example and not limitation in the figures of the accompanying drawings in which like references indicate similar elements.
Various embodiments and aspects will be described with reference to details discussed below, and the accompanying drawings will illustrate the various embodiments. The following description and drawings are illustrative and are not to be construed as limiting. Numerous specific details are described to provide a thorough understanding of various embodiments. However, in certain instances, well-known or conventional details are not described in order to provide a concise discussion of embodiments.
Reference in the specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in conjunction with the embodiment can be included in at least one embodiment. The appearances of the phrase “in one embodiment” and/or “in some embodiments” in various places in the specification do not necessarily all refer to the same embodiment. The processes depicted in the figures that follow are performed by processing logic that comprises hardware (e.g. circuitry, dedicated logic, etc.), software, or a combination of both. Although the processes are described below in terms of some sequential operations, it should be appreciated that some of the operations described may be performed in a different order. Moreover, some operations may be performed in parallel rather than sequentially. Throughout the specification, and in the claims, the term “connected” means a direct electrical connection between the things that are connected, without any intermediary devices. The term “coupled” means either a direct electrical connection between the things that are connected, or an indirect connection through one or more passive or active intermediary devices. The term “circuit” means one or more passive and/or active components that are arranged to cooperate with one another to provide a desired function. The term “signal” means at least one current signal, voltage signal or data/clock signal. The meaning of “a”, “an”, and “the” include plural references. The meaning of “in” includes “in” and “on”. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
As previously described, future directions of telecommunications support a move to mm Wave frequencies. To serve prominent frequency bands for mm Wave 5G communications globally, it is desirable that the device front end and the antenna supports a wide frequency range from 24 GHz to 43.5 GHz. The demands from the evolving wireless communication technology place stringent requirements on terminal device antenna design. The embodiments of the present disclosure address these demands by proposing a wideband polarization diverse antenna element suitable for mm Wave MIMO antenna arrays. Therefore, the embodiments of the present disclosure may play a positive and vital role in boosting and promoting the development of the new generation of wireless communication systems where such antennas are in great demand.
Polarization diversity is achieved through two radiating arms 110, 120 arranged in orthogonal fashion on a suitable substrate material 150, which may be a multi-layer printed circuit board. Referring to
The first radiating arm 110 may be arranged to be higher (e.g., vertically offset) from the second radiating arm 120. Stated another way, the first radiating arm 110 may be offset from the second radiating arm in a third direction that is orthogonal to the first and second directions. The offset may be a small fraction of the wavelength at the operating frequencies. In some embodiments, the first radiating arm 110 may be offset from the second radiating arm 120 in the third direction by 0.127 mm to 0.254 mm.
A signal may be applied to the first radiating arm 110 through a first port 170 and feed coupling (not shown). A signal may be applied to the second radiating arm 120 through a second port 175 and associated feed coupling 180. Orthogonal polarization is obtained by exciting the first and second radiating arms 110, 120 independently through the corresponding ports 170, 175. A differential feeding mechanism is adopted to excite the first and second radiating arms 110, 120 over a wide frequency bandwidth. In some embodiments, one of the first and second radiating arms 110, 120 may be provided with a signal that is vertically polarized while the other of the first and second radiating arms 110, 120 is provided with a signal that is horizontally polarized. The embodiments of the present invention are not limited to configurations in which the signal polarizations are horizontal and vertical. In some embodiments, one of the first and second radiating arms 110, 120 may be provided with a first signal that is polarized while the other of the first and second radiating arms 110, 120 is provided with a second signal that is polarized orthogonally to the first signal. In some embodiments, the first and second radiating arms 110, 120 may be configured to support transmission of first and second signals that range from 24 GHz to 43.5 GHz.
Each of the first and second radiating arms 110, 120 may include radiating elements. For example, the first radiating arm 110 may include opposing first radiating elements 115, and the second radiating arm 120 may include opposing second radiating elements 125. When viewed in plan, the first radiating elements 115 of the first radiating arm 110 may be arranged adjacent the second radiating elements 125 of the second radiating arm 120. The arrangement of the first and second radiating elements 115, 125 of the first and second radiating arms 110, 120 will be discussed further herein with respect to
In some embodiments, the first and second radiating arms 110, 120 may be disposed in a substrate 150. In some embodiments, all or a part of the substrate 150 may be a portion of a printed circuit board (PCB). For example, in some embodiments, the first and second radiating arms 110, 120 may be arranged on different layers within the PCB. Thus, in some embodiments, the first radiating arm 110 may be separated from the second radiating arm 120 by at least a portion of the PCB.
In some embodiments, the radiating elements of the first and second radiating arms 110, 120 may be respectively disposed on and/or over parasitic posts 130. For example, the first radiating element 115 of the first radiating arm 110 may be disposed on and/or over a first parasitic post 130, and the second radiating element 125 of the second radiating arm may be disposed on and/or over a second parasitic post 130. The parasitic post 130 may have a longitudinal axis that extends vertically toward a respective one of the first or second radiating arms 110, 120. For example, as previously described, the first radiating arm 110 may be offset from the second radiating arm 120 in a third (e.g., vertical) direction. In some embodiments, the longitudinal axis of the parasitic post 130 may extend in the third direction and the parasitic post 130 may be offset from the respective one of the first or second radiating arms 110, 120. In some embodiments, the parasitic post 130 may have a cylinder shape, but the embodiments of the present disclosure are not limited to such a configuration. In some embodiments, the parasitic posts 130 are optional.
In some embodiments, the parasitic posts 130 may be formed of a conductive material, such as a conductive metal. Other conductive materials may be utilized without deviating from the scope of the present disclosure. In some embodiments, the parasitic posts 130 may be disposed within the substrate 150. For example, in some embodiments, portions of the substrate 150 (e.g., a portion of a PCB) may be between the parasitic post 130 and the first or second radiating arm 110, 120.
As will be described further herein, this particular element configuration of the antenna element 100 may help to improve impedance bandwidth of the antenna element 100 to cater to the frequency requirements of modern communication systems. The vertical parasitic posts 130 under the first and second radiating arms 110, 120, as can be seen in
Referring to
The first radiating element 115 may have a first outer edge 115A that is adjacent a second outer edge 125A of the second radiating element 125. The first outer edge 115A may be one of a plurality of outer edges of the first radiating element 115. For example, the first radiating element 115 of
The first outer edge 115A of the first radiating element 115 may be a closest edge of the plurality of edges of the first radiating element 115 to the second radiating element 125. Similarly, the second outer edge 125A of the second radiating element 125 may be a closest edge of the second radiating element 125 to the first radiating element 115. As will be discussed further with respect to
The first outer edge 115A of the first radiating element 115 may extend substantially in parallel to the second outer edge 125A of the second radiating element 125 (e.g., when viewed in plan). As used herein, “substantially parallel” means that a distance between the two outer edges 115A, 125A does not vary by more than 10% along the length of the adjacent outer edges 115A, 125A. The parallel arrangement of the first and second outer edges 115A, 125A may assist in improving the performance of the antenna element 100. The two outer edges 115A, 125A may be horizontally offset by a small fraction of the wavelength at the operating frequencies. In some embodiments, a horizontal distance X between the first and second outer edges 115A, 125A may be between 0.127 mm and 0.3 mm.
Though the discussion with respect to
In some embodiments, each of the first and second radiating elements 115, 125 are disposed on parasitic posts 130. In some embodiments, when viewed in plan, the parasitic post 130 may be disposed near a center of the first and second radiating elements 115, 125. In some embodiments, at least a portion of the parasitic post 130 may be vertically overlapped by one of the first and second radiating elements 115, 125.
In some embodiments, the parasitic post 130 may be offset in the first direction (e.g., the vertical direction) from a respective one of the first and second radiating elements 115, 125. This vertical offset may be a small fraction of the wavelength at the frequency of operation. In some embodiments, the radiating elements 115, 125 of the antenna element 100 may be disposed horizontally about a quarter wavelength of the operating frequency from the ground plane, and the height of the vertical parasitic posts 130 may be close to about a quarter wavelength at the frequency of operation. In some embodiments, the vertical offset between the parasitic post 130 in the first direction (e.g., the vertical direction) and a respective one of the first and second radiating elements 115, 125 may be about one percent of a free-space wavelength at the mid frequency of the wideband antenna. In some embodiments, this offset may be approximately 0.127 mm. In some embodiments, the offsets between various ones of the parasitic posts 130 and a first or second radiating element 115, 125 under which it is disposed in substantially the same (e.g., within 10% of one another). In some embodiments, the offsets between various ones of the parasitic posts 130 and a first or second radiating element 115, 125 under which it is disposed may differ from one another (e.g., by more than 10%). In some embodiments, the length in the first direction (e.g., the vertical direction) of a parasitic post 130 that is under one of the second radiating elements l25 is smaller than the length in the first direction (e.g., the vertical direction) of another parasitic post 130 that is under one of the first radiating elements l15, though the embodiments of the present disclosure are not limited thereto.
As previously described, in some embodiments, one or more of the parasitic posts 130 may be omitted. For example, in some embodiments a parasitic post 130 may be under one of the first radiating elements 115 but not under other ones of the first radiating elements 115. Similarly, in some embodiments a parasitic post 130 may be under one of the second radiating elements 125 but not under other ones of the second radiating elements 125. In some embodiments, a parasitic post 130 may be under one or more of the first radiating elements 115 but not under the second radiating elements 125. In some embodiments, the parasitic posts 130 may be omitted altogether.
The impedance chart of
Referring to
One of the issues with a dipole like element such as that described herein is that the beamwidth of the radiation pattern in the E-plane (i.e., the plane along the direction of surface currents or the electric fields) decreases as frequency increases. In other words, as the element’s electrical length (length in terms of wavelength) increases, a squeeze in radiation pattern is observed in the E-plane. This can be seen for the curve 920A in
Though the parasitic posts 130 provide additional improvements to the antenna element 100, some embodiments of the antenna element 100 may nonetheless show improved performance over conventional devices while omitting the parasitic posts 130. Thus, embodiments of the present disclosure may still provide an improved antenna element 100 despite the absence of the parasitic posts 130.
In
In a radio receiver circuit, the RF frontend 201 is a generic term for all the circuitry between the antenna up to and including the mixer stage. It consists of all the components in the receiver that process the signal at the original incoming radio frequency, before it is converted to a lower frequency, e.g., IF. In microwave and satellite receivers it is often called the low-noise block (LNB) or low-noise downconverter (LND) and is often located at the antenna, so that the signal from the antenna can be transferred to the rest of the receiver at the more easily handled intermediate frequency. A baseband processor 202 is a device (a chip or part of a chip) in a network interface that manages all the baseband processing functions to process baseband signals.
In a radio transmitter circuit, the RF frontend 201 is a generic term for all the circuitry between the mixer stage up to and including the antenna. It consists of all the components in the transmitter that processes the signal at the more easily handled intermediate frequency, IF, before it is converted to a radio frequency, e.g., RF, for transmission. In microwave and satellite transmitters it is often called the block upconverter (BUC), which makes up the “transmit” side of the system, and is often used in conjunction with an LNB, which makes up the “receive” side of the system.
In some embodiments, RF frontend module 201 includes one or more RF transceivers, where each of the RF transceivers transmits and receives RF signals within a particular frequency band (e.g., a particular range of frequencies such as non-overlapped frequency ranges) via one of a number of RF antennas. One or more of the RF antennas may include the antenna element 100 as described herein.
With reference to
Method 1500 begins at block 1510, a first radiating arm may be provided. The first radiating arm may be similar to one of the first and second radiating arms 110, 120 discussed herein. In some embodiments, the first radiating arm may be provided over a reflector. The reflector may be similar to the suitable substrate material 150 discussed herein. In some embodiments, the first radiating arm may be configured for a signal polarized in a particular direction.
At block 1515, the configuration of the first radiating arm may be adjusted. For example, a length of the arm length and/or a distance of the first radiating arm from the reflector.
The adjustments of block 1515 may be continued until block 1520, when a resonance is obtained in a lower side of the desired operating frequency band. Examples of the types of resonance that may be obtained are illustrated, for example, in curves 520A and 520B in
At block 1525, a second radiating arm may be provided. The second radiating arm may be similar to one of the first and second radiating arms 110, 120 discussed herein. The second radiating arm may be arranged orthogonal to the first radiating arm in a manner similar to that disclosed herein with respect to the first and second radiating arms 110, 120. In some embodiments, the second radiating arm may be configured for a signal polarized in an orthogonal direction from that of the first radiating arm.
At block 1530, the configuration of the second radiating arm may be adjusted. For example, a length of the arm length of the second radiating arm may be adjusted. In addition, vertical and horizontal offsets between adjacent edges of the first radiating arm and the second radiating arm may be adjusted. The adjacent edges of the first and second radiating arms may be similar to the first and second edges 115A, 125A discussed herein.
The adjustments of block 1530 may be continued until block 1535, when two distinct resonances are obtained. Examples of the types of resonance that may be obtained are illustrated, for example, in curves 510A and 510B in
At block 1540, parasitic monopoles may be added. The parasitic monopoles may be similar to the parasitic posts 130 discussed herein. The parasitic monopoles may be arranged under the first and second radiating arms in a manner similar to that disclosed herein with respect the parasitic posts 130 in relation to the first and second radiating arms 110, 120.
At block 1545, the arm dimensions of the first and second radiating arms may be adjusted again. In some embodiments, the adjustments to the first and second radiating arms will be made based on the measured and/or simulated performance of the antenna element. In some embodiments, the adjustments may be made in light of a particular range of operating frequency at which the antenna element is intended to operate.
At block 1550, the position and vertical dimensions of the parasitic monopoles may be adjusted. In some embodiments, the adjustments to the parasitic monopoles will be made based on the measured and/or simulated performance of the antenna element. In some embodiments, the adjustments may be made in light of a particular range of operating frequency at which the antenna element is intended to operate.
The result of the method illustrated and described with respect to
Embodiments of the present invention are not limited to any particular application. It can be used in various wireless applications and at various frequencies and with different multiple access methods, advantageously at radio frequencies such as the fifth generation mobile communications standard frequencies.
In the foregoing specification, specific exemplary embodiments have been described. It will be evident that various modifications may be made to those embodiments without departing from the broader spirit and scope set forth in the following claims. The specification and drawings are, accordingly, to be regarded in an illustrative sense rather than a restrictive sense.