Patent Application
20230378654
Embodiments of the disclosure relate to an antenna arrangement for an electronic device, the antenna arrangement comprising an antenna radiator and a plurality of antenna feeds.
Electronic apparatuses, such as smartphones, have to support more and more cellular radio technology, for example, 5G requires new radio technology to be added since the used frequency range will be expanded from so-called sub-6 GHz to millimeter-wave (mmWave) frequencies, e.g., above 20 GHz. To achieve mmWave frequencies, the antenna array is usually implemented in a module that is fixed to the main printed circuit board (PCB) of the smartphone. The PCB may comprise an antenna array where the main radiation beam direction is the broadside direction, i.e., perpendicular to the display and back cover of the smartphone. The PCB may also be configured such that the main radiation beam direction is the end-fire direction, i.e., parallel to the display and the back cover of the smartphone. In the latter case, the antenna array usually occupies some space within the metal rim of the apparatus.
These mmWave modules leave very limited space available within the apparatus for other components such as additional antennas, in particular due to several modules being necessary in order to achieve sufficiently good multi-surface spherical beam coverage.
Furthermore, modern smartphones require antenna systems that can cover multiple frequency bands with wide bandwidths and several multiple input multiple output (MIMO) antennas operating in each band.
Currently, antennas for the 700-960 MHz and 1700-2700 MHz bands are usually realized using sections of the metal rim of the apparatus, i.e., a space which is already occupied by, e.g., mmWave antenna arrays. In order to be able to fit in additional antennas, such as sub-6 GHz 5G NR antennas, other free space within the smartphone has to be utilized for these additional antennas.
The greatest challenge to providing additional antenna elements within a smartphone is, in other words, the extremely limited volume available, especially as far as the thickness of the smartphone is concerned. Current low-profile antennas are often too thick and integrating them with existing structures and components is often very difficult.
Therefore, there is a need for new antennas that have low profiles and which can be easily integrated into the difficult environment inside modern smartphones.
It is an object to provide an improved antenna arrangement for an electronic apparatus. The foregoing and other objects are achieved by the features of the independent claim. Further implementation forms are apparent from the dependent claims, the description, and the figures.
According to a first aspect, there is provided an antenna arrangement comprising a dielectric element, at least one conductive element, an antenna radiator, and a plurality of exciter elements. The antenna radiator is arranged at a first surface of the dielectric element and at a distance from the conductive element such that a gap is formed between the antenna radiator and a first surface of the conductive element. The exciter elements extend at least partially through the gap and are arranged on or adjacent to the conductive element.
Such a configuration allows utilizing an already existing gap, which gap, e.g., is necessary to accommodate battery expansion and manufacturing tolerances, for creating the radiating currents of an antenna arrangement. By using an already existing volume inside an electronic apparatus, effectively utilizing one volume for two purposes, it is possible to decrease the physical size of the antenna while providing a larger effective volume as compared to state-of-the-art solutions. Furthermore, using multiple exciter elements enables control and adaption of the coupling level between the feeds of the antenna arrangement. When properly designed, this coupling can be used to cancel parts of the reflected power and increase the radiated power. Additionally, only a smaller section of the area of the dielectric element needs to be used for the antenna arrangement. This is an advantage since the remaining area of the dielectric element, such as the back cover, can accommodate other required components such as camera modules.
In a possible implementation form of the first aspect, the antenna radiator comprises a conductive material and is one of printed, sintered, painted, laminated, or deposited onto the first surface of the dielectric element, or molded into the dielectric element. This not only allows the antenna radiator to have any suitable shape or dimensions, but also allows it to be applied onto, or into, the dielectric element in several suitable ways.
In a further possible implementation form of the first aspect, the antenna radiator is conductively isolated from the conductive element. A conductive element, such as the main chassis of an electronic apparatus, is electrically too large to contribute to radiation above about 2 GHz frequencies in an efficient and controlled manner. However, with a separate local chassis antenna, in the form of an antenna radiator, the antenna dimensions can be designed so that the antenna radiates optimally at the desired frequency bands.
In a further possible implementation form of the first aspect, the exciter elements are arranged along a peripheral edge of the antenna radiator. With such placement, the exciter elements do not affect or influence the gap volume necessary to, e.g., accommodate battery expansion.
In a further possible implementation form of the first aspect, the exciter elements are superposed with the antenna radiator. This allows the exciter elements to be coupled to each other and/or the number of exciter elements to be reduced.
In a further possible implementation form of the first aspect, the antenna arrangement comprises at least a first pair of exciter elements and a second pair of exciter elements, the first pair of exciter elements being decoupled from the second pair of exciter elements. This allows the antenna arrangement to effectively form two frequency tunable antennas that cannot be controlled independently but are always tuned to the same frequency, achieving an increased antenna efficiency.
In a further possible implementation form of the first aspect, a first exciter element is coupled to a second exciter element of the first pair of exciter elements, and a first exciter element is coupled to a second exciter element of the second pair of exciter elements, and
In a further possible implementation form of the first aspect, the first exciter element of the first pair of exciter elements is coupled to the first exciter element of the second pair of exciter elements, and the second exciter element of the first pair of exciter elements is coupled to the second exciter element of the second pair of exciter elements, the first exciter elements are coupled to the second exciter elements, the couplings being made by means of a second feeding network and exciting a second antenna signal having a second polarization, the second polarization being orthogonal to the first polarization. This way, two frequency tunable antennas are formed which achieve orthogonal polarization.
In a further possible implementation form of the first aspect, each exciter element is galvanically, capacitively, or inductively coupled to at least one other exciter element and/or antenna radiator. Galvanic coupling provides a reliable and well-known type of coupling. Non-contacting couplings, like capacitive and inductive couplings, can be manufactured, e.g., on the PCB or the apparatus chassis along with any required matching networks and other control circuits.
In a further possible implementation form of the first aspect, the first polarization is −45° and the second polarization is +45°, improving the equality in received signal levels and improving coverage in congested environments.
In a further possible implementation form of the first aspect, the first feeding network and/or the second feeding network comprise a power divider coupled to a first phase shifter and a second phase shifter, a phase of the second exciter element being shifted by 180° compared to a phase of the first exciter element, the proper phase shift between the feeding signals facilitating optimal performance of the multi-feed operation.
In a further possible implementation form of the first aspect, the conductive element is configured such that the distance between the first surface of the dielectric element and the first surface of the conductive element is variable, allowing conductive elements such as batteries to expand thermally and/or manufacturing tolerances to be considered.
In a further possible implementation form of the first aspect, the antenna arrangement comprises at least one tunable element for tuning the resonant frequencies of the antenna arrangement. Tunable matching components can be used to tune the impedance of the feed port of the exciter elements to be optimal for each frequency sub-band.
In a further possible implementation form of the first aspect, the tunable element is a varactor, a switch, and/or a phase shifter, allowing tuning to be executed by means of a variety of components.
In a further possible implementation form of the first aspect, the resonant frequencies are tuned by the tunable element(s) in response to the variation of the distance between the first surface of the dielectric element and the first surface of the conductive element, allowing the gap between the dielectric element and conductive element to not only accommodate thermal expansion of the conductive element but to also provide an effective antenna volume.
In a further possible implementation form of the first aspect, the tunable element(s) are configured to optimize radiation modes of the antenna arrangement and/or to use a change in the radiation modes for tuning the resonant frequencies.
In a further possible implementation form of the first aspect, the conductive element is a battery, the variation of distance being due to thermal expansion of the battery. This allows existing components to contribute to the performance of the antenna arrangement.
In a further possible implementation form of the first aspect, the antenna radiator is a patch radiator, the patch radiator optionally comprising at least one slot. Such an antenna radiator takes up very little space, as seen in the direction of the gap, and is easily fitted to or molded into the dielectric element.
In a further possible implementation form of the first aspect, the patch radiator comprises two slots, the slots extending in parallel in a first direction and being offset in a second direction perpendicular to the first direction. By providing a second slot, a further resonance can be excited without significantly affecting the resonances excited by the patch and first slot.
In a further possible implementation form of the first aspect, the patch radiator comprises four slots, each slot extending colinearly with one of the slots and orthogonally to the remaining slots, each slot extending from one peripheral edge, and towards a center point, of the patch radiator. This allows the number of exciter elements to be reduced, while providing an antenna arrangement that effectively comprises two frequency tunable antennas having orthogonal polarization and which are controlled simultaneously to the same frequency.
In a further possible implementation form of the first aspect, wherein the slots form a cross-shape, the cross-shape being interrupted at the common center point. By providing additional slots, further resonances can be excited.
In a further possible implementation form of the first aspect, the tunable elements are arranged at the peripheral edges of the patch radiator, each tunable element being arranged adjacent one of the slots, allowing the operating frequency of each slot to be tuned.
In a further possible implementation form of the first aspect, the dimensions of the slots and/or the number of slots is configured to generate one or more desired resonant frequencies, improving the performance of the antenna arrangement.
In a further possible implementation form of the first aspect, the antenna radiator comprises several individual radiator sections separated by dielectric gaps, allowing a multimode antenna arrangement.
According to a second aspect, there is provided an apparatus comprising the antenna arrangement according to the above, a display, and a housing, the housing comprising the dielectric element of the antenna arrangement, the conductive element of the antenna arrangement being one of a battery, a printed circuit board, and an apparatus chassis.
This solution allows an empty volume within the apparatus, e.g. due to the gap between the conductive element and apparatus housing, to be utilized by antennas. Furthermore, no additional printed circuit board is required for the antenna arrangement since the excitation elements, feeding structures, and matching and tuning circuits can be arranged on the main printed circuit board.
This and other aspects will be apparent from and the embodiments described below.
In the following detailed portion of the present disclosure, the aspects, embodiments, and implementations will be explained in more detail with reference to the example embodiments shown in the drawings, in which:
The antenna radiator 4 is arranged at a first surface 2a of the dielectric element 2 and at a distance D, D′ from the conductive element 3 such that the gap 5 is formed between the antenna radiator 4 and a first surface 3a of the conductive element 3. As shown in
The antenna radiator 4 may comprise a conductive material and be one of printed, sintered, painted, laminated, or deposited onto the first surface 2a of the dielectric element 2, or molded into the dielectric element 2. For example, the antenna radiator 4 may be a metal pattern printed on the inner surface of a glass back cover, or may be painted thereon. The antenna radiator may be completely planar or follow the shape of the first surface 2a of the dielectric element 2.
Furthermore, the antenna radiator 4 may be conductively isolated from the conductive element 3, and the ground plane of the apparatus 10.
The antenna radiator 4 may comprise several individual radiator sections separated by dielectric gaps, as shown in
The antenna radiator 4 may be a patch radiator 8, the patch radiator 8 optionally comprising at least one slot 9 as shown in
A patch radiator 8 comprising one slot is shown in
In an embodiment comprising two slots 9, the slots 9 may extend in parallel in a first direction while being offset in a second direction perpendicular to the first direction, as shown in
When the patch radiator 8 comprises four slots 9, each slot 9 may extend colinearly with one of the slots 9 and orthogonally to the remaining slots 9, each slot 9 extending from one peripheral edge, and towards a center point, of the patch radiator 8. In other words, the slots 9 together form an X or cross shape, the X or cross being interrupted at their common center point such that the center point comprises radiator material, as shown in
The dimensions of the antenna radiator 4 define the resonance modes. The longitudinal dimension of the antenna radiator 4 defines the lowest resonance, and the orthogonal dimension (width) of the antenna radiator 4 defines the highest resonance.
The dimensions of the slots 9 and/or the number of slots 9 may be configured to generate one or more desired resonant frequencies. By providing a second slot, a third resonance can be excited without significantly affecting the two initial resonances excited by the patch and first slot.
By increasing the slot 9 width, the current path along the longest dimension may be made longer, shifting the first resonant frequency and the third resonant frequency down. The same happens for the second resonant frequency. Since the second resonant frequency is created from a collaborative use of exciting elements 6 and it uses a diagonal current pattern, see the diagonally arranged exciter elements 6 in
The radiation modes of the antenna radiator 4 are mainly affected by two factors, i.e., the size and shape of the antenna radiator 4 and the exciter elements 6. In addition to the radiating modes, also the impedances need to be designed simultaneously so that the multiple feeds can be utilized effectively.
The exciter elements 6, exciting radiating currents in the antenna radiator 4, may be arranged along a peripheral edge of the antenna radiator 4, as shown in
Optionally, the exciter elements 6 may be superposed with the antenna radiator 4, as shown in
With one exciter element 6, one radiation mode may be effectively excited, along the longest dimension of the antenna radiator 4. The S-parameters of the antenna have two resonances in the 3.3-4.2 GHz frequency band. By providing several exciter elements 6, a further radiation mode is excited as a result of the combined operation of both exciter elements 6. Similarly, for the S-parameters, a new resonance is created so that three resonances appear in the desired frequency band.
The exciter elements 6 may be any suitable, conventional type of exciter element 6.
When the exciter elements 6 are superposed with the antenna radiator 4, the antenna arrangement may be configured to comprise at least a first pair of exciter elements 6a, 6b and a second pair of exciter elements 6c, 6d, the first pair of exciter elements 6a, 6b being decoupled from the second pair of exciter elements 6c, 6d as shown in
A first exciter element 6a may be coupled to a second exciter element 6b of the first pair of exciter elements 6a, 6b, and a first exciter element 6c may be coupled to a second exciter element 6d of the second pair of exciter elements 6c, 6d. Furthermore, the first pair of exciter elements 6a, 6b may be coupled to the second pair of exciter elements 6c, 6d, the couplings being made by means of a first feeding network 13a and exciting a first antenna signal having a first polarization.
Simultaneously, or optionally, the first exciter element 6a of the first pair of exciter elements 6a, 6b may be coupled to the first exciter element 6c of the second pair of exciter elements 6c, 6d, and the second exciter element 6b of the first pair of exciter elements 6a, 6b may be coupled to the second exciter element 6d of the second pair of exciter elements 6c, 6d. The first exciter elements 6a, 6c may be coupled to the second exciter elements 6b, 6d, the couplings being made by means of a second feeding network 13b and exciting a second antenna signal having a second polarization. Preferably, the second polarization is orthogonal to the first polarization. The first polarization may, e.g., be −45° and the second polarization +45°.
The first feeding network 13a may comprise a power divider coupled to a first phase shifter and the second feeding network 13b may comprise a power divider coupled to a second phase shifter. The phase of the second exciter element 6b, 6d is preferably shifted by 180° compared to the phase of the first exciter element 6a, 6c. The phase difference between the exciter elements 6 can be changed on each sub-band to achieve optimal performance.
Since the values of the phase shift depend on the frequency, the antenna operation can be tuned to operate on different frequency sub-bands by varying the phase. In addition, tunable elements 7, discussed further below, can be used to tune the impedances of the exciter element 6 ports to be optimal for each sub-band. A multi-channel transceiver IC may generate the required arbitrary phases for the feeding signal which are then fed to the exciter elements 7 through matching networks with fixed components (capacitors/inductors) and tunable elements 7.
Each exciter element 6 may be galvanically, capacitively, or inductively coupled to the antenna radiator 4, as suggested in
The antenna arrangement 1 may comprise at least one tunable element 7 for tuning the resonant frequencies of the antenna arrangement 1.
The resonant frequencies may be tuned by the tunable elements 7 in response to the variation of the distance D, D′ between the first surface 2a of the dielectric element 2 and the first surface 3a of the conductive element 3.
Furthermore, the tunable elements 7 may be configured to optimize radiation modes of the antenna arrangement 1 and/or to use a change in the radiation modes for tuning the resonant frequencies.
In other words, the tunable elements 7 can be used to adapt the operation of the antenna arrangement 1 to different types of changes in the operation environment, for example, compensating for a decrease in antenna efficiency due to swelling of the battery or actively reducing the specific absorption rate (SAR) when operated next to the user's body.
In one example of compensating changes in the device structure, battery swelling, the gap between the battery 3b and the dielectric element 2 with the antenna radiator 4 decreases from 0.75 mm to 0.45 mm. By utilizing the phase differences and optimal tunable element settings, significant improvements in terms of efficiency can be achieved. By utilizing the tunable elements 7, a clear decrease in SAR can be seen in most of the frequency band.
The tunable elements 7 may be arranged at the peripheral edges of the patch radiator 8, as shown in
The various aspects and implementations have been described in conjunction with various embodiments herein. However, other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed subject-matter, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage.
The reference signs used in the claims shall not be construed as limiting the scope. Unless otherwise indicated, the drawings are intended to be read (e.g., cross-hatching, arrangement of parts, proportion, degree, etc.) together with the specification, and are to be considered a portion of the entire written description of this disclosure. As used in the description, the terms “horizontal”, “vertical”, “left”, “right”, “up” and “down”, as well as adjectival and adverbial derivatives thereof (e.g., “horizontally”, “rightwardly”, “upwardly”, etc.), simply refer to the orientation of the illustrated structure as the particular drawing figure faces the reader. Similarly, the terms “inwardly” and “outwardly” generally refer to the orientation of a surface relative to its axis of elongation, or axis of rotation, as appropriate.
This application is a continuation of International Application No. PCT/EP2021/052058, filed on Jan. 29, 2021, the disclosure of which is hereby incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/EP2021/052058 | Jan 2021 | US |
| Child | 18362577 | US |
