Antenna apparatus and wireless transceiver comprising the same

Abstract

A dual-resonant antenna apparatus is provided, which exhibits improved impedance bandwidth, cross-polarization, and isolation and is not vulnerable to the excitation of spurious surface waves. More specifically, at least one antenna element and a resonant structure are provided on a non-conductive substrate such that at least one continuous conductive sidewall of the resonant structure surrounds the antenna element(s) and defines a resonant cavity filled with a dielectric material that covers the antenna element(s). Each antenna element is configured to excite a TM mode, while the dielectric material and dimensions of the resonant cavity are selected such that the resonant structure is configured to excite a TE mode. In a preferred embodiment, the TM mode is a TM 01 mode, while the TE mode is a TE 111 mode.

Description

[0001] ANTENNA APPARATUS AND WIRELESS TRANSCEIVER COMPRISING THE SAME

[0002] TECHNICAL FIELD

[0003] The present disclosure relates generally to the field of wireless antennas. In particular, the present disclosure relates to an antenna apparatus configured to excite both a transverse electric (TE) mode and a transverse magnetic (TM) mode while suppressing the excitation of spurious surface waves, as well as to a wireless transceiver comprising the antenna apparatus.

[0004] BACKGROUND

[0005] Although the number of antennas in mobile user equipment (UEs) (e.g., a mobile phone, handset, etc.) has increased, the volume reserved for the antennas has remained the same or even reduced. Therefore, the antennas should have dimensions as small as possible. Furthermore, the antennas should have an appealing appearance and be preferably invisible for users.

[0006] A conventional patch antenna is a single resonant structure, which makes it difficult to fulfil impedance bandwidth requirements. The normal component of an electric field is dominant in the patch antenna, for which reason it will easily excite surface waves in mobile UEs, thereby causing distortions of a main radiation beam. The bandwidth of the patch antenna can be increased, e.g., by introducing a dual-resonant structure. A dual resonance can be achieved by using a resonant cavity. The patch antenna itself can provide a first resonance, while the cavity walls can provide a second resonance. However, the drawbacks of such dual-resonant structures are their thickness and the presence of slots in the cavity walls which are needed to achieve the second resonance. In practice, the design of the slots is challenging, especially when dual feeding and a dual band are required. Furthermore, the dual-resonant structure with the slots in the cavity walls still suffers from the excitation of spurious surface waves due to the dominant normal component of the electric field.

[0007] Dielectric resonator antennas (DRAs) offer a potential alternative with a smaller antenna aperture. They are characterized by dual polarization and the minimal excitation of spurious surface waves. However, the DRAs are typically thick enough and usually limited to a single resonance, thereby having a narrow impedance bandwidth. SUMMARY

[0008] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure.

[0009] It is an objective of the present disclosure to provide a dual-resonant antenna structure that is characterized by improved impedance bandwidth, cross-polarization, and isolation and is not vulnerable to the excitation of spurious surface waves.

[0010] The objective above is achieved by the features of the independent claims in the appended claims. Further embodiments and examples are apparent from the dependent claims, the detailed description, and the accompanying drawings.

[0011] According to a first aspect, an antenna apparatus is provided, which comprises a non-conductive substrate, at least one antenna element provided on the non-conductive substrate, and a resonant structure provided on the non-conductive substrate. Each of the at least one antenna element is configured to excite a TM mode. The resonant structure has at least one continuous conductive sidewall surrounding each of the at least one antenna element and a cavity defined by the at least one continuous conductive sidewall. The cavity is filled with a first dielectric material covering each of the at least one antenna element. The first dielectric material and dimensions of the cavity are selected such that the resonant structure is configured to excite a TE mode. The antenna apparatus thus configured can provide one resonance in the TE mode and the other resonance in the TM mode, i.e., may operate as a dual-resonant structure. In the antenna apparatus thus configured, the normal component of the electric field is minimized by the presence of the dielectric-filled cavity with the slot-free sidewall(s), which results in the suppression of spurious surface waves in the antenna apparatus. It should be noted that the TE mode may be efficiently tuned by changing either all dimensions of the cavity or the dimensions of the cavity in a XY-plane only (for example, when the dimension of the cavity in the Z- direction is fixed due to some restrictions applied to the thickness of the antenna apparatus). Thus, the antenna apparatus may exhibit improved impedance bandwidth, cross-polarization, and isolation. Furthermore, since there is no slit or slot in the sidewall(s) of the resonant structure, the antenna apparatus is mechanically robust.

[0012] In one exemplary embodiment of the first aspect, the TM mode is a TM 01 mode, and the TE mode is a TE 111 mode. Thus, the antenna apparatus according to the first aspect may merge two basis resonant modes, TM 01 and TE 111, which may provide a wide impedance bandwidth. Furthermore, these TM and TE modes may be needed to satisfy some specific demands in the field of wireless communications.

[0013] In one exemplary embodiment of the first aspect, each of the at least one antenna element is configured as a patch antenna. Patch antennas are characterized by compact dimensions and are one of the simplest to design. Moreover, they offer a simple polarized emission solution, especially at high frequencies. Thus, the patch antennas are easy to design and fabricate, which may simplify the fabrication process of the antenna apparatus.

[0014] In one exemplary embodiment of the first aspect, the patch antenna is a dual-feed patch antenna. In this case, dual feeding means dual polarization. That is, the dual-feed patch antenna may have a slanted or linear polarization. Dual polarization in turn implies a Multiple-Input Multiple-Output (MIMO) feature which may be used either to improve a link quality measured by a diversity gain, or to enhance a data rate measured by a spatial multiplexing gain. Diversity is typically used in conditions where channel fading is a problem (i.e., low Signal-to-Noise Ratio (SNR)), whereas spatial multiplexing is used in a high-SNR regime.

[0015] In one exemplary embodiment of the first aspect, the first dielectric material has a dielectric permittivity ranging from 2 to 15. These dielectric materials may provide better TE (especially, TE 111) mode excitation in the antenna apparatus.

[0016] In one exemplary embodiment of the first aspect, the first dielectric material comprises a host dielectric medium and an array of metal patches embedded in the host dielectric medium. When metal patches are introduced in a dielectric material, they introduce some capacitance, and the effect is the same as if one increases the dielectric permittivity of the substrate. This is beneficial if the substrate material is fixed, e.g., to Dk = 3, and the thickness of the antenna apparatus is fixed as well. In this case, by using the array of metal patches in the host dielectric medium, one can artificially increase the Dk of the substrate to tune the TE mode resonance at a desired frequency.

[0017] In one exemplary embodiment of the first aspect, the antenna apparatus further comprises at least one second dielectric material covering the first dielectric material. Each of the at least one second dielectric material has a dielectric permittivity ranging from 3 to 30. Said at least one second dielectric material may be used to additionally tune the TE mode excited by the resonant structure. It should be noted that said at least one second dielectric material may be part of a mobile UE in order not to increase the thickness of the antenna apparatus. For example, the second dielectric material may refer to some part of a display glass and / or camera lens which may be used in the mobile UE.

[0018] In one exemplary embodiment of the first aspect, the non-conductive substrate is configured as a printed circuit board (PCB) having a cavity arranged under the cavity of the resonant structure. The cavity of the PCB is filled with a third dielectric material, and each of the at least one antenna element is provided on the third dielectric material. The presence of this (optional) dielectric-filled cavity in the PCB may additionally improve the performance of the antenna apparatus, i.e., the excitation of the TM and TE modes therein. Furthermore, the cavity of the PCB allows the antenna element(s) to be fed from below, thereby making the antenna apparatus more compact in size.

[0019] In one exemplary embodiment of the first aspect, the third dielectric material has a dielectric permittivity ranging from 2 to 8. These dielectric materials may provide better TE (especially, TE 111) mode excitation in the antenna apparatus.

[0020] According to a second aspect, a wireless transceiver is provided. The wireless transceiver comprises at least one antenna apparatus according to the first aspect, a transmitting unit, and a receiving unit. The transmitting unit is coupled to the at least one antenna apparatus and configured to produce a radio signal and transmit the produced radio signal via the at least one antenna apparatus. The receiving unit is coupled to the at least one antenna apparatus and configured to receive a radio signal via the at least one antenna apparatus and perform signal processing of the received radio signal. The wireless transceiver thus configured may operate in a wide bandwidth by using two TE and TM modes.

[0021] Other features and advantages of the present disclosure will be apparent upon reading the following detailed description and reviewing the accompanying drawings.

[0022] BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present disclosure is explained below with reference to the accompanying drawings in which:

[0024] FIGs 1 A and IB show schematic isometric section views of an antenna apparatus according to a first exemplary embodiment, namely: FIG. 1A shows the antenna apparatus with an empty cavity of a resonant structure, and FIG. IB shows the antenna apparatus when the cavity of the resonant structure is filled with a dielectric material; FIG. 2 shows a schematic isometric section view of an antenna apparatus according to a second exemplary embodiment, which differs from the first exemplary embodiment in having an additional dielectric material covering the cavity and sidewalls of the resonant structure;

[0025] FIG. 3 shows a schematic isometric section view of an antenna apparatus according to a third exemplary embodiment, which differs from the first exemplary embodiment in having an additional dielectric-filled cavity in a non-conductive substrate under an antenna element;

[0026] FIGs 4A and 4B show schematic views of an antenna apparatus according to a fourth exemplary embodiment, which differs from the first to third exemplary embodiments in having a conformal antenna array, namely: FIG. 4A shows an isometric section view of the antenna apparatus, and FIG. 4B shows an isometric partial view of the antenna apparatus (with all dielectric materials removed);

[0027] FIG. 5 shows S-parameters (i.e., Si l and S21) versus a frequency for an antenna apparatus according to the present disclosure in a low-frequency band;

[0028] FIG. 6 shows S-parameters (i.e., Si l and S21) versus a frequency for an antenna apparatus according to the present disclosure in a high-frequency band; and

[0029] FIG. 7 shows a schematic block diagram of a wireless transceiver according to one exemplary embodiment.

[0030] DETAILED DESCRIPTION

[0031] Various embodiments of the present disclosure are further described in more detail with reference to the accompanying drawings. However, the present disclosure may be embodied in many other forms and should not be construed as limited to any certain structure or function discussed in the following description. In contrast, these embodiments are provided to make the description of the present disclosure detailed and complete.

[0032] According to the detailed description, it will be apparent to the ones skilled in the art that the scope of the present disclosure encompasses any embodiment thereof, which is disclosed herein, irrespective of whether this embodiment is implemented independently or in concert with any other embodiment of the present disclosure. For example, the apparatuses disclosed herein may be implemented in practice by using any numbers of the embodiments provided herein. Furthermore, it should be understood that any embodiment of the present disclosure may be implemented using one or more of the features presented in the appended claims.

[0033] The word “exemplary” is used herein in the meaning of “used as an illustration”. Unless otherwise stated, any embodiment described herein as “exemplary” should not be construed as preferable or having an advantage over other embodiments.

[0034] Any positioning terminology, such as “left”, “right”, “top”, “bottom”, “above” “below”, “upper”, “lower”, “horizontal”, “vertical”, etc., may be used herein for convenience to describe one element’s or feature's relationship to one or more other elements or features in accordance with the figures. It should be apparent that the positioning terminology is intended to encompass different orientations of the apparatus disclosed herein, in addition to the orientation(s) depicted in the figures. As an example, if one imaginatively rotates the apparatus in the figures 90 degrees clockwise, elements or features described as “left” and “right” relative to other elements or features would then be oriented, respectively, “above” and “below” the other elements or features. Therefore, the positioning terminology used herein should not be construed as any limitation of the present disclosure.

[0035] Although the numerative terminology, such as “first”, “second”, “third”, “fourth”, etc., may be used herein to describe various embodiments and features, these embodiments and features should not be limited by this numerative terminology. This numerative terminology is used herein only to distinguish one feature or embodiment from another feature or embodiment. For example, a first dielectric material could be renamed a second dielectric material, and vice versa, without departing from the teachings of the present disclosure.

[0036] The exemplary embodiments disclosed herein provide a dual-resonant antenna structure, which exhibits improved impedance bandwidth, cross-polarization, and isolation and is not vulnerable to the excitation of spurious surface waves. More specifically, at least one antenna element and a resonant structure are provided on a non-conductive substrate such that at least one continuous conductive sidewall of the resonant structure surrounds the antenna element(s) and defines a resonant cavity filled with a dielectric material that covers the antenna element(s). Each antenna element is configured to excite a TM mode, while the dielectric material and dimensions of the resonant cavity are selected such that the resonant structure is configured to excite a TE mode. In a preferred embodiment, the TM mode is a TM 01 mode, while the TE mode is a TE 111 mode. FIGs 1A and IB show schematic isometric section views of an antenna apparatus 100 according to a first exemplary embodiment. The antenna apparatus 100 comprises a non-conductive substrate 102 and an antenna element 104 provided on the substrate 102. The antenna element 104 is configured to excite a TM mode, for which reason it may be implemented as a patch antenna. The antenna apparatus 100 further comprises a resonant structure provided on the same (top) surface of the substrate 102 as the antenna element 104. The resonant structure comprises conductive (e.g., metal) sidewalls 106 surrounding the antenna element 104 and defining a rectangular cavity 108 (see FIG. 1A) to be filled with a dielectric material 110 (see FIG. IB). As can be seen, the antenna element 104 is located at the bottom of the cavity 108, so that its thickness is small compared to the total thickness of the antenna apparatus 100. The conductive sidewalls 106 are continuous in the sense that they do not have any slits or slots. The cavity 108 filled with the dielectric material 110 may be considered as a DRA configured to excite a TE mode. More specifically, the horizontal xy- and vertical z-dimensions of the cavity 108 defines the TE mode according to the following equations: where f0is the resonant frequency of the TE mode, c is the speed of light, Eris the permittivity of the dielectric material 110, a is the dimension of the cavity 108 in the y-axis, b is the dimension of the cavity 108 in the x-axis, and d is the dimension of the cavity 108 in the z-axis.

[0037] Thus, by properly selecting the parameters £r, a, b, and d, one can tune the TE mode to be excited by the resonant structure in the antenna apparatus 100. Preferably, the permittivity Erof the dielectric material 110 ranges from 2 to 15.

[0038] In some embodiments, if d is fixed (i.e., it is impossible to change the height of the cavity 108, e.g., due to the limited volume available for the antenna apparatus 100 in a certain mobile UE, such as a smartphone), the TE mode may be tuned by changing the horizontal xy-dimensions of the cavity 108 and the Erof the dielectric material 110. In the meantime, a proper srmay additionally be achieved by using the so-called artificial dielectric as the dielectric material 110. Such an artificial dielectric may comprise a host dielectric medium and an array of metal patches embedded in the host dielectric medium such as to provide a proper relative permittivity.

[0039] It should be noted that the number, arrangement, and shape of the constructive elements constituting the antenna apparatus 100, which are shown in FIGs 1A and IB, are not intended to be any limitation of the present disclosure, but merely used to provide a general idea of how the constructive elements may be implemented within the antenna apparatus 100. For example, there may be more than one antenna element 104 provided adjacent to each other on the substrate 102, with each of the antenna elements 104 being implemented either as a planar antenna (e.g., a microstrip antenna, slot antenna, patch antenna, etc.) or a non-planar antenna (e.g., a rectangular waveguide antenna, etc.). Furthermore, the cavity 108 may have any polygonal (e.g., triangular, pentagonal, etc.) or curved (e.g., oval, circular, etc.) shape. For example, if the cavity 108 has a circular shape, then there is a single continuous conductive sidewall 106 surrounding the antenna element(s) 104. Additionally, the continuous conductive sidewalls 106 may not necessarily cover the whole area of the substrate 102 outside the cavity 108; in other words, the continuous conductive sidewalls 106 may be made thinner (as schematically shown by dashed lines in FIG. 1 A).

[0040] FIG. 2 shows a schematic isometric section view of an antenna apparatus 200 according to a second exemplary embodiment. Like the antenna apparatus 100, the antenna apparatus 200 comprises a non-conductive substrate 202, as well as an antenna element 204 and a resonant structure which are provided on the same surface of the substrate 202. Similarly, the resonant structure comprises continuous conductive sidewalls 206 surrounding the antenna element 204 and defining a rectangular cavity filled with a first dielectric material 208 that covers the antenna element 204. At the same time, the antenna apparatus 200 differs from the antenna apparatus 100 in that it further comprises a second dielectric material 210 covering the cavity and the sidewalls 206 of the resonant structure. The second dielectric material 210 may have a permittivity ranging from 3 to 30. Again, the antenna element 204 is configured to excite a TM mode (e.g., TM 01), while the resonant structure is configured to excite a TE mode (e.g., TE 111). It should be noted that the TE mode is created in the antenna apparatus 200 by the whole dielectric volume above the antenna element 204 (i.e., the combination of the first and second dielectric materials 208 and 210), and the cavity defined by the sidewalls 206 virtually defines its xy-dimensions (even if, e.g., the second dielectric material 210 and / or any other dielectric material above the cavity fully covers not only the cavity itself but also the sidewalls 206). In some embodiments, the second dielectric material 210 may be (part of) a dielectric component used in a mobile UE in which the antenna apparatus 200 is to be mounted. For example, the dielectric component may be a display glass and / or a camera lens used in the UE.

[0041] It should be also noted that the second dielectric material 210 may be arranged such that it covers the sidewalls 206 only partly or does not cover the sidewalls 206 at all (i.e., the second dielectric material 210 may be arranged on the first dielectric material 208 only).

[0042] FIG. 3 shows a schematic isometric section view of an antenna apparatus 300 according to a third exemplary embodiment. Like the antenna apparatuses 100 and 200, the antenna apparatus 300 comprises a non-conductive substrate 302, as well as an antenna element 304 and a resonant structure which are provided on the same surface of the substrate 302. Similarly, the resonant structure comprises continuous conductive sidewalls 306 surrounding the antenna element 304 and defining a rectangular cavity filled with a first dielectric material 308 that covers the antenna element 304. Again, the antenna element 304 is configured to excite a TM mode (e.g., TM 01), while the resonant structure is configured to excite a TE mode (e.g., TE 111). At the same time, the antenna apparatus 300 differs from the antenna apparatuses 100 and 200 in that there is an additional cavity provided in the substrate 302 under the antenna element 304. The additional cavity is filled with an additional dielectric material 310 that preferably has a permittivity ranging from 2 to 8. For example, such an additional cavity may be made in a PCB serving as the substrate 302. Furthermore, one or more feeding lines may go through the dielectric material 310 to the antenna element 304.

[0043] It should be noted that the apparatus 300 may also be provided with an additional dielectric material covering the cavity (i.e., the dielectric material 308). In other words, such an additional dielectric material may be implemented, for example, as the second dielectric material 210 in the antenna apparatus 200.

[0044] FIGs 4A and 4B show schematic views of an antenna apparatus 400 according to a fourth exemplary embodiment. More specifically, FIG. 4A shows an isometric section view of the antenna apparatus 400, and FIG. 4B shows an isometric partial view of the antenna apparatus 400. Unlike the antenna apparatuses 100-300, the antenna apparatus 400 comprises a non- conductive substrate 402 and an array of antenna elements 404 (e.g., patch antennas) arranged thereon. The antenna apparatus 400 further comprises a resonant structure which is implemented such that each antenna element 404 is surrounded by continuous conductive sidewalls 406 of the resonant structure. The sidewalls 406 define an array of rectangular cavities 408 (see FIG. 4B) each filled with a first dielectric material 410 covering the antenna element 404. Again, each of the antenna elements 404 is configured to excite a TM mode (e.g., TM 01), while each of the cavities 408 of the resonant structure is configured to excite a TE mode (e.g., TE 111). As also shown in FIG. 4A, the antenna apparatus 400 further comprises a second dielectric material 412 attached to the first dielectric material 410, for example, by means of an adhesive tape 414 or any other adhesive agent or means (e.g., glue). For example, the first and second dielectric materials 410 and 412 may be implemented in the same or similar manner as the first and dielectric materials 208 and 210, respectively. Additionally, the substrate 402 comprises an array of additional cavities each formed under the corresponding antenna element 404 and filled with a third dielectric material 416 which may be the same or similar to the third dielectric material 310.

[0045] FIG. 5 shows S-parameters (i.e., Si l and S21) versus a frequency for an antenna apparatus according to the present disclosure in a low-frequency band. More specifically, the antenna apparatus for the low-frequency band has been implemented as the combination of the apparatuses 200 and 300 (i.e., with the joint use of the dielectric materials 210 and 310) in the following form: the antenna element implemented as a patch antenna has dimensions of 1.8 mm x 1.8 mm; the permittivity of the third dielectric material under the antenna element (i.e., the dielectric material 310) is 6.15; the permittivity of the first dielectric material covering the antenna element in the cavity of the resonant structure is 3; the permittivity of the second dielectric material covering the first dielectric material is 14.5; and the cavity of the resonant structure has XY-dimensions of 2.2 mm x 2.2 mm and a Z- dimension of 0.5 mm.

[0046] As can be seen, the TM 01 mode resonance occurs at about 25 GHz, while the TE 111 mode resonance occurs at about 29 GHz.

[0047] FIG. 6 shows S-parameters (i.e., Si l and S21) versus a frequency for an antenna apparatus according to the present disclosure in a high-frequency band. More specifically, the antenna apparatus for the high-frequency band has been again implemented as the combination of the apparatuses 200 and 300 (i.e., with the joint use of the dielectric materials 210 and 310) in the following form: the antenna element implemented as a patch antenna has dimensions of 1.6 mm x 1.6 mm; the permittivity of the third dielectric material under the antenna element (i.e., the dielectric material 310) is 3; the permittivity of the first dielectric material covering the antenna element in the cavity of the resonant structure is 3; the permittivity of the second dielectric material covering the first dielectric material is 6.2; and the cavity of the resonant structure has XY-dimensions of 2.2 mm x 2.2 mm and a Z- dimension of 0.6 mm.

[0048] As can be seen, the TM 01 mode resonance occurs at 35 GHz, while the TE 111 mode resonance occurs at 41 GHz.

[0049] FIG. 7 shows a schematic block diagram of a wireless transceiver 700 according to one exemplary embodiment. As used in the embodiments disclosed herein, the wireless transceiver may refer to an apparatus configured to perform data reception and transmission by using radio waves. The radio waves may refer to a type of electromagnetic radiation that occurs in different frequency bands of the radio spectrum (e.g., in the so-called centimeter-wave (cmWave) and millimeter-wave (mmWave) bands). The radio waves are used, for example, in wireless communications, such as point-to-point communications, intersatellite links, and point-to- multipoint communications, etc. However, the application of the radio waves is not limited to wireless communications only, and they may be also used, for example, for (air, ground or marine) vehicle navigation and control, road obstacle detection, distance ranging (radar applications), contactless vital-sign monitoring, occupancy detection, etc. For this reason, the wireless transceiver 700 may be used in the same use scenarios as the radio waves. Furthermore, the wireless transceiver 700 may be implemented as part of a user equipment (UE) that may refer to a wireless customer premises equipment (CPE) (e.g., a wireless router, switch, etc.), a mobile device, a mobile station, a terminal, a subscriber unit, a mobile phone, a cellular phone, a smart phone, a cordless phone, a personal digital assistant (PDA), a wireless communication device, a desktop computer, a laptop computer, a tablet computer, a single-board computer (SBC) (e.g., a Raspberry Pi device), a gaming device, a netbook, a smartbook, an ultrabook, a medical device or medical equipment, a biometric sensor, a wearable device (e.g., a smart watch, smart glasses, a smart wrist band, etc.), an entertainment device (e.g., an audio player, a video player, etc.), a vehicular component or sensor (e.g., a driver-assistance system), a smart meter / sensor, an unmanned vehicle (e.g., an industrial robot, a quadcopter, etc.) and its component (e.g., a self-driving car computer), industrial manufacturing equipment, a global positioning system (GPS) device, an Internet-of- Things (loT) device, an Industrial loT (IIoT) device, a machine-type communication (MTC) device, a group of Massive loT (MIoT) or Massive MTC (mMTC) devices / sensors, or any other suitable device that uses the radio waves for operation. In some embodiments, the UE may refer to at least two collocated and interconnected UEs thus defined.

[0050] As shown in FIG. 7, the wireless transceiver 700 comprises an antenna apparatus 702, a transmitting (TX) unit 704, and a receiving (RX) unit 706. The antenna apparatus 702 may be implemented as any of the antenna apparatus 100-400, or any combination thereof. The TX unit 704 is coupled to the antenna apparatus 702 and configured to produce a radio signal and transmit the produced radio signal via the antenna apparatus 702. The RX unit 706 is coupled to the antenna apparatus 702 and configured to receive a radio signal via the antenna apparatus 702 and perform signal processing (e.g., properly decode) of the received radio signal.

[0051] Although the exemplary embodiments of the present disclosure are described herein, it should be noted that any various changes and modifications could be made in the embodiments of the present disclosure, without departing from the scope of legal protection which is defined by the appended claims. In the appended claims, the word “comprising” does not exclude other elements or operations, 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 measures cannot be used to advantage.

Claims

CLAIMS1. An antenna apparatus comprising: a non-conductive substrate; at least one antenna element provided on the non-conductive substrate, each of the at least one antenna element being configured to excite a transverse magnetic (TM) mode; and a resonant structure provided on the non-conductive substrate, the resonant structure having at least one continuous conductive sidewall surrounding each of the at least one antenna element and a cavity defined by the at least one continuous conductive sidewall; wherein the cavity is filled with a first dielectric material, the first dielectric material covering each of the at least one antenna element; and wherein the first dielectric material and dimensions of the cavity are selected such that the resonant structure is configured to excite a transverse electric (TE) mode.

2. The antenna apparatus of claim 1, wherein the TM mode is a TM 01 mode, and the TE mode is a TE 111 mode.

3. The antenna apparatus of claim 1 or 2, wherein each of the at least one antenna element is configured as a patch antenna.

4. The antenna apparatus of claim 3, wherein the patch antenna is a dual-feed patch antenna.

5. The antenna apparatus of any one of claims 1 to 4, wherein the first dielectric material has a dielectric permittivity ranging from 2 to 15.

6. The antenna apparatus of any one of claims 1 to 5, wherein the first dielectric material comprises a host dielectric medium and an array of metal patches embedded in the host dielectric medium.

7. The antenna apparatus of any one of claims 1 to 6, further comprising at least one second dielectric material covering the first dielectric material, each of the at least one second dielectric material having a dielectric permittivity ranging from 3 to 30.

8. The antenna apparatus of any one of claims 1 to 7, wherein the non-conductive substrate is configured as a printed circuit board (PCB) having a cavity arranged under the cavity of the resonant structure, the cavity of the PCB being filled with a third dielectric material, and wherein each of the at least one antenna element is provided on the third dielectric material.

9. The antenna apparatus of claim 8, wherein the third dielectric material has a dielectric permittivity ranging from 2 to 8.

10. A wireless transceiver comprising: at least one antenna apparatus according to any one of claims 1 to 9; a transmitting unit coupled to the at least one antenna apparatus, the transmitting unit being configured to produce a radio signal and transmit the produced radio signal via the at least one antenna apparatus; and a receiving unit coupled to the at least one antenna apparatus, the receiving unit being configured to receive a radio signal via the at least one antenna apparatus and perform signal processing of the received radio signal.

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