WO2020073643A1

WO2020073643A1 - Wideband vertical polarized end-fire antenna

Info

Publication number: WO2020073643A1
Application number: PCT/CN2019/084975
Authority: WO
Inventors: Wei Huang; Ping SHI; Xiaoyin He
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2018-10-10
Filing date: 2019-04-29
Publication date: 2020-04-16
Also published as: CN112805878B; CN112805878A

Abstract

An antenna includes two ground planes spaced apart in a first dimension, a three-dimensional (3D) cavity slot in between the two ground planes, wherein the 3D cavity slot comprises an aperture in the first dimension, and an antenna feed configured to feed the antenna inside the 3D cavity slot, wherein the antenna feed is short circuited to the 3D cavity slot, and the antenna feed and the 3D cavity slot form a closed loop capable of generating a magnetic field around the closed loop that excites an unbalanced TE20 mode inside the 3D cavity slot.

Description

WIDEBAND VERTICAL POLARIZED END-FIRE ANTENNA

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. provisional Application Serial No. 62/743,587, filed on October 10, 2018 and U.S. provisional Application Serial No. 62/766,602, filed on December 14, 2018, which are hereby incorporated by reference in their entireties.

TECHNICAL FIELD

This disclosure relates to wideband vertical polarized end-fire antenna, for example, for 5G mmWave communications.

BACKGROUND

Various emerging applications, e.g., virtual reality (VR) , augmented reality (AR) , big data analytics, artificial intelligence (AI) , three-dimensional (3D) media, ultra-high definition transmission video, etc. have created a significant growth in data volume in wireless communications networks. 5G expands spectrum usage to both below 6GH and above 24GHz (which is known as mmWave) and opens up a large amount of bandwidth for high data rate and capacity.

SUMMARY

The present disclosure relates to a wideband vertical polarized (V-pol) end-fire antenna.

A first aspect relates to an antenna for wireless communications, the antenna comprising two ground planes spaced apart in a first dimension, a three-dimensional (3D) cavity slot in between the two ground planes, wherein the 3D cavity slot comprises an aperture in the first dimension, and an antenna feed configured to feed the antenna inside the 3D cavity slot, wherein the antenna feed is short circuited to the 3D cavity slot, and the antenna feed and the 3D cavity slot form a closed loop capable of generating a magnetic field around the closed loop that excites an unbalanced TE20 mode inside the 3D cavity slot. Thus, a wideband vertical polarized end-fire antenna, for example, for 5G mmWave communications can be realized.

The antenna facilitates an efficient solution for wireless communications over a wide bandwidth for high data rate and capacity, especially for 5G mmWave communications. The antenna can have good linearity for mmWave communications and can enhance transmission capacity of a multiple input and multiple output (MIMO) diversity system of a 5G mobile device.

In a first implementation form of the apparatus according to the first aspect as such, the antenna feed comprises a loop-shape antenna feed. The loop-shape antenna feed provides an efficient solution to create an unbalanced TE20 mode and generate a 2 ^nd resonance frequency to achieve a wide bandwidth and good linearity in terms of radiation pattern of the antenna.

In a second implementation form of the apparatus according to the first aspect as such or any preceding implementation form of the first aspect, the loop-shape antenna feed comprises a first portion substantially in parellel with at least one of the two ground planes, and a second portion substantially vertical to one of the two ground planes, and a third portion substantially vertical to one of the two ground planes, wherein the second portion is closer to the aperture than the third portion. Thus, in some instances, the loop-shape antenna feed can be easier in implementation or manufacturing compared to other types of antenna feed such as an L-shape antenna feed.

In a third implementation form of the apparatus according to the first aspect as such or any preceding implementation form of the first aspect, the second portion is substantially close to the aperture. Thus, the antenna feed excites a TE10 mode insides the 3D cavity slot, and achieves vertical polarization.

In a fourth implementation form of the apparatus according to the first aspect as such or any preceding implementation form of the first aspect, the aperture is of a length of λ ₁/2, wherein λ ₁ is a wavelength corresponding to a first resonant frequency f ₁ of the antenna.

In a fifth implementation form of the apparatus according to the first aspect as such or any preceding implementation form of the first aspect, the antenna feed excites a TE10 mode and generates an E-field along the first dimension at the first resonant frequency f ₁ of the antenna, resulting in a vertical polarization of the antenna.

In a sixth implementation form of the apparatus according to the first aspect as such or any preceding implementation form of the first aspect, the aperture is of a width of w, wherein w is substantially less than λ ₁/10. Thus, the antenna can be implemented with compact vertical dimension and achieve strong vertical polarization on end-fire/side coverage.

In a seventh implementation form of the apparatus according to the first aspect as such or any preceding implementation form of the first aspect, the antenna feed is λ ₂/4 away from one end of the aperture, wherein λ ₂ is a wavelength corresponding to a second resonant frequency f ₂ of the antenna. Thus, the bandwidth of the antenna can be configured by configuring the distance of the antenna feed relative to the end of the aperture.

In an eighth implementation form of the apparatus according to the first aspect as such or any preceding implementation form of the first aspect, the two ground planes are formed by a first layer and a second layer of a printed circuit board (PCB) , and the antenna feed is formed by a third or more layers and one or more vias of the PCB. Thus, the antenna can be implemended using PCBs.

In a ninth implementation form of the apparatus according to the first aspect as such or any preceding implementation form of the first aspect, the antenna has a vertical polarization along the first dimension, and the first dimension is a thickness dimension of the PCB. Thus, the antenna can be implemended using PCBs with compact vertical dimension.

A second aspect relates to a wireless apparatus comprising for wireless communications, the wireless apparatus comprising an antenna, the antenna comprising two ground planes spaced apart in a first dimension, a three-dimensional (3D) cavity slot in between the two ground planes, wherein the 3D cavity slot comprises an aperture in the first dimension, and an antenna feed configured to feed the antenna inside the 3D cavity slot, wherein the antenna feed is short circuited to the 3D cavity slot, and the antenna feed and the 3D cavity slot form a closed loop capable of generating a magnetic field around the closed loop that excites an unbalanced TE20 mode inside the 3D cavity slot. Thus, a wideband vertical polarized end-fire antenna, for example, for 5G mmWave communications can be realized.

The wireless apparatus facilitates an efficient solution for wireless communications over a wide bandwidth for high data rate and capacity, especially for 5G mmWave communications. The antenna can have good linearity for mmWave communications and can enhance transmission capacity of a multiple input and multiple output (MIMO) diversity system of a 5G mobile device.

In a first implementation form of the wireless apparatus according to the second aspect as such, the antenna feed comprises a loop-shape antenna feed. The loop-shape antenna feed provides an efficient solution to create an unbalanced TE20 mode and generate a 2 ^nd resonance frequency to achieve a wide bandwidth and good linearity in terms of radiation pattern of the antenna.

In a second implementation form of the wireless apparatus according to the second aspect as such or any preceding implementation form of the second aspect, the loop-shape antenna feed comprises a first portion substantially in parellel with at least one of the two ground planes, and a second portion substantially vertical to one of the two ground planes, and a third portion substantially vertical to one of the two ground planes, wherein the second portion is closer to the aperture than the third portion. Thus, in some instances, the loop-shape antenna feed can be easier in implementation or manufacturing compared to other types of antenna feed such as an L-shape antenna feed.

In a third implementation form of the wireless apparatus according to the second aspect as such or any preceding implementation form of the second aspect, the second portion is substantially close to the aperture. Thus, the antenna feed excites a TE10 mode insides the 3D cavity slot, and achieves vertical polarization.

In a fourth implementation form of the wireless apparatus according to the second aspect as such or any preceding implementation form of the second aspect, the aperture is of a length of λ ₁/2, wherein λ ₁ is a wavelength corresponding to a first resonant frequency f ₁ of the antenna.

In a fifth implementation form of the wireless apparatus according to the second aspect as such or any preceding implementation form of the second aspect, the antenna feed excites a TE10 mode and generates an E-field along the first dimension at the first resonant frequency f ₁ of the antenna, resulting in a vertical polarization of the antenna.

In a sixth implementation form of the wireless apparatus according to the second aspect as such or any preceding implementation form of the second aspect, the aperture is of a width of w, wherein w is substantially less than λ ₁/10. Thus, the antenna can be implemented with compact vertical dimension and achieve strong vertical polarization on end-fire/side coverage.

In a seventh implementation form of the wireless apparatus according to the second aspect as such or any preceding implementation form of the second aspect, the antenna feed is λ ₂/4 away from one end of the aperture, wherein λ ₂ is a wavelength corresponding to a second resonant frequency f ₂ of the antenna. Thus, the bandwidth of the antenna can be configured by configuring the distance of the antenna feed relative to the end of the aperture.

In an eighth implementation form of the wireless apparatus according to the second aspect as such or any preceding implementation form of the second aspect, the two ground planes are formed by a first layer and a second layer of a printed circuit board (PCB) , and the antenna feed is formed by a third or more layers and one or more vias of the PCB. Thus, the antenna can be implemended using PCBs.

In a ninth implementation form of the wireless apparatus according to the second aspect as such or any preceding implementation form of the second aspect, the antenna has a vertical polarization along the first dimension, and the first dimension is a thickness dimension of the PCB. Thus, the antenna can be implemended using PCBs with compact vertical dimension.

A third aspect relates to an antenna array for wireless communications, the antenna array comprising a plurality of antennas, wherein each antenna comprising two ground planes spaced apart in a first dimension, a three-dimensional (3D) cavity slot in between the two ground planes, wherein the 3D cavity slot comprises an aperture in the first dimension, and an antenna feed configured to feed the antenna inside the 3D cavity slot, wherein the antenna feed is short circuited to the 3D cavity slot, and the antenna feed and the 3D cavity slot form a closed loop capable of generating a magnetic field around the closed loop that excites an unbalanced TE20 mode inside the 3D cavity slot. Thus, a wideband vertical polarized end-fire antenna, for example, for 5G mmWave communications can be realized.

The antenna array facilitates an efficient solution for wireless communications over a wide bandwidth for high data rate and capacity, especially for 5G mmWave communications. The antenna can have good linearity for mmWave communications and can enhance transmission capacity of a multiple input and multiple output (MIMO) diversity system of a 5G mobile device.

In a first implementation form of the apparatus according to the third aspect as such, the antenna feed comprises a loop-shape antenna feed. The loop-shape antenna feed provides an efficient solution to create an unbalanced TE20 mode and generate a 2 ^nd resonance frequency to achieve a wide bandwidth and good linearity in terms of radiation pattern of the antenna.

In a second implementation form of the antenna array according to the third aspect as such or any preceding implementation form of the third aspect, the loop-shape antenna feed comprises a first portion substantially in parellel with at least one of the two ground planes, and a second portion substantially vertical to one of the two ground planes, and a third portion substantially vertical to one of the two ground planes, wherein the second portion is closer to the aperture than the third portion. Thus, in some instances, the loop-shape antenna feed can be easier in implementation or manufacturing compared to other types of antenna feed such as an L-shape antenna feed.

In a third implementation form of the antenna array according to the third aspect as such or any preceding implementation form of the third aspect, the second portion is substantially close to the aperture. Thus, the antenna feed excites a TE10 mode insides the 3D cavity slot, and achieves vertical polarization.

In a fourth implementation form of the antenna array according to the third aspect as such or any preceding implementation form of the third aspect, the aperture is of a length of λ ₁/2, wherein λ ₁ is a wavelength corresponding to a first resonant frequency f ₁ of the antenna.

In a fifth implementation form of the antenna array according to the third aspect as such or any preceding implementation form of the third aspect, the antenna feed excites a TE10 mode and generates an E-field along the first dimension at the first resonant frequency f ₁ of the antenna, resulting in a vertical polarization of the antenna.

In a sixth implementation form of the antenna array according to the third aspect as such or any preceding implementation form of the third aspect, the aperture is of a width of w, wherein w is substantially less than λ ₁/10. Thus, the antenna can be implemented with compact vertical dimension and achieve strong vertical polarization on end-fire/side coverage.

In a seventh implementation form of the antenna array according to the third aspect as such or any preceding implementation form of the third aspect, the antenna feed is λ ₂/4 away from one end of the aperture, wherein λ ₂ is a wavelength corresponding to a second resonant frequency f ₂ of the antenna. Thus, the bandwidth of the antenna can be configured by configuring the distance of the antenna feed relative to the end of the aperture.

In an eighth implementation form of the antenna array according to the third aspect as such or any preceding implementation form of the third aspect, the two ground planes are formed by a first layer and a second layer of a printed circuit board (PCB) , and the antenna feed is formed by a third or more layers and one or more vias of the PCB. Thus, the antenna can be implemended using PCBs.

In a ninth implementation form of the antenna array according to the third aspect as such or any preceding implementation form of the third aspect, the antenna has a vertical polarization along the first dimension, and the first dimension is a thickness dimension of the PCB. Thus, the antenna can be implemended using PCBs with compact vertical dimension.

The details of one or more implementations of the subject matter of this specification are set forth in the accompanying drawings and the description. Other features, aspects, and advantages of the subject matter will become apparent from the description, the drawings, and the claims.

DESCRIPTION OF DRAWINGS

FIG. 1A and 1B are schematic diagrams illustrating an example process for configuring a slot antenna by folding a ground plane, according to an implementation.

FIG. 2 is a schematic diagram illustrating an example process for configuring a three-dimensional (3D) cavity slot, according to an implementation.

FIG. 3 is a schematic diagram illustrating portions of an example wideband vertical polarized (V-pol) antenna, according to an implementation.

FIG. 4 is a plot illustrating an example return loss of an example wideband V-pol antenna, according to an implementation.

FIG. 5 is a plot illustrating an example electric field (E-field) of an example wideband V-pol antenna in a TE10 mode, according to an implementation.

FIG. 6A is a plot illustrating an example E-field of an example wideband V-pol antenna in a TE20 mode, according to an implementation.

FIG. 6B is a plot illustrating an example magnetic field (H-field) of the example wideband V-pol antenna in a TE20 mode, according to an implementation.

[Corrected under Rule 26, 10.07.2019]
FIG. 6C is a plot illustrating an example typical balanced TE20 mode that has approximately equal E-fields with opposite directions, according to an implementation.

FIG. 7A is a plot illustrating an example E-field of an example wideband V-pol antenna in the TE10 mode, according to an implementation.

FIG. 7B is a plot illustrating an example E-field of the example wideband V-pol antenna in the unbalanced TE20 mode, according to an implementation.

FIG. 7C is a plot illustrating an example H-field of the example wideband V-pol antenna in the TE10 mode, according to an implementation.

FIG. 7D is a plot illustrating an example H-field of the example wideband V-pol antenna in the unbalanced TE20 mode, according to an implementation.

FIG. 8A is a schematic diagram illustrating portions of another example 3D slot antenna, according to an implementation.

FIG. 8B is a plot illustrating an example return loss of the another example 3D slot antenna, according to an implementation.

FIG. 9A is a schematic diagram illustrating portions of yet another example 3D slot antenna, according to an implementation.

FIG. 9B is a plot illustrating an example return loss of the yet another example 3D slot antenna, according to an implementation.

FIGS. 10A-10B are plots illustrating gain patterns of the example wideband V-pol antenna 300, according to an implementation.

FIGS. 11A-11B are plots and illustrating gain vs. angle patterns of an example wideband V-pol antenna in E and H-planes at the 1 ^st resonance frequency, respectively, according to an implementation.

FIGS. 12A-12B are plots and illustrating gain vs. angle patterns of the example wideband V-pol antenna in E and H-planes at the 2 ^nd resonance frequency, respectively, according to an implementation.

FIG. 13 is a plot illustrating an example array gain of an example wideband V-pol antenna array, according to an implementation.

Like reference numbers and designations in the various drawings indicate like elements.

DETAILED DESCRIPTION

The following detailed description describes a wideband vertical polarized (V-pol) end-fire antenna and is presented to enable any person skilled in the art to make and use the disclosed subject matter in the context of one or more particular implementations.

Various modifications, alterations, and permutations of the disclosed implementations can be made and will be readily apparent to those of ordinary skill in the art, and the general principles defined may be applied to other implementations and applications, without departing from scope of the disclosure. In some instances, details unnecessary to obtain an understanding of the described subject matter may be omitted so as to not obscure one or more described implementations with unnecessary detail inasmuch as such details are within the skill of one of ordinary skill in the art. The present disclosure is not intended to be limited to the described or illustrated implementations, but to be accorded the widest scope consistent with the described principles and features.

In a wireless communications system, especially a 5G system operating on wide frequency bands (e.g., mmWave frequency bands in a 5G system) , high signal attenuation during propagation through air interfaces can restrict the wireless link budget. Smartly designed beamforming algorithms for multiple array antennas are desirable to improve the spatial multiplexing gain for multiple input and multiple output (MIMO) systems, especially under channel conditions where mmWave mobile terminals are subject to unpredictable orientations. For example, polarization of the beam can be dynamically adaptable to real-life channel environments to increase or maximize the efficiency. In some implementations, two separate linear polarizations (horizontal and vertical) are desirable for both the base station and mobile terminal phase arrays to enhance the capacity of a MIMO diversity system under line-of-sight (LOS) and non-LOS (NLOS) conditions.

It can be challenging to realize a linear polarized antenna element with electrically small vertical profiles. As consumer devices continues to shrink in size, the antenna is desirable to be designed in a small dimension. Moreover, for dipole antennas, antenna size is dependent on the operational frequency. As such, it is more challenging to reduce the size of antennas for the 5G system operating in mmWave frequency bands.

In some implementations, horizontal polarization can be implemented using typical planar dipole or Yagi-inspired antennas. If simply rotating a horizontal dipole 90 degree to a vertical orientation, the original horizontal dipole with a half-wavelength dimension is no longer electrically small enough. Moreover, the interference on linearity and polarization isolation also need to be carefully considered and addressed when both polarization antenna elements co-exist within the same or close space.

The disclosure provides an antenna system for solving the above problems. The described antenna system can support vertical polarization on end-fire coverage with electrically small vertical profiles for mmWave communications. The described antenna system can support dual polarizations on end-fire/side coverage with compact vertical dimension. The antenna system enables mmWave antenna implementation inside of a compact mobile device, for example, for enhancing capacity of a MIMO diversity system of a 5G mobile device.

FIG. 1A and 1B are schematic diagrams illustrating an example process 100 for configuring a slot antenna by folding a ground plane, according to an implementation. FIG. 1A shows a ground plane 110 with a slot aperture 150. The ground plane 110 can be of conducting material. For example, the ground plane 110 can be a planar metal sheet. The slot aperture 150 has a length of L = λ/2 and a width of w, where λ is a wavelength corresponding to a first resonant frequency of the slot antenna. The slot aperture 150 has two

longitudinal edges

101 and 103.

In some implementations, to achieve a small vertical profile (e.g., less than λ ₀/10, where λ ₀ is a wavelength corresponding to a first resonant frequency of the antenna) , the ground plane 110 can be folded along two

folding lines

102 and 104. The two

folding lines

102 and 104 are in line or along the two

longitudinal edges

101 and 103 of the slot aperture 150, respectively. As a result of the folding, the two

sides

112 and 114 of the ground plane 110 can form two opposing ground planes, for example, in a U shape as the u-shape structure 215 shown in FIG. 2.

FIG. 2 is a schematic diagram illustrating an example process 200 for configuring a three-dimensional (3D) cavity slot 210, according to an implementation. As shown in FIG. 2, the 3D cavity slot 210 can be configured by folding a planar slot antenna 205 that includes a ground plane 220 with a slot aperture 250. The slot aperture 250 has a length of λ/2 in the horizontal dimension and a width of w in the vertical dimension. The ground plane 220 and the slot aperture 250 can be, for example, the ground plane 110 and slot aperture 150, as shown in FIG. 1, respectively.

The ground plane 220 can be folded along two longitudinal edges of the slot aperture 250 to form a u-shape structure 215, for example, in a similar manner as described with respect to FIG. 1. The u-shape structure 215 thus has two

ground planes

222 and 224, for example, substantially in parallel, where “substantially” in parallel includes in parallel or functionally equivalent to in parallel so long as functionality (e.g., structural or electrical functionality) can be maintained. For example, if the two

ground planes

222 and 224 have an angle less than 1 or 2 degrees relative to each other, the two

ground planes

222 and 224 are considered substantially in parallel with each other.

A back cavity 255 can be added to the u-shape structure 215 to form the 3D cavity slot 210 with the slot aperture 250. As a result, the 3D cavity slot 210 has a length of L=λ/2, a width of w, and a depth of d, as shown in FIG. 2. The slot aperture 250 radiates in the thickness dimension of the u-shape structure 215 (i.e., the width or vertical dimension of the slot aperture 250 as indicated by w in FIG. 2) .

As shown in FIG. 2, the 3D cavity slot 210 has a box shape. The 3D cavity slot 210 can be a cuboid, a cube, or of another shape that is defined by six sides or

surfaces

202, 204, 232, 234, 242, and 244. In some implementations, each of the six

sides

202, 204, 232, 234, 242, and 244 is substantially in a regulator shape. In some implementations, the slot aperture 250 forms or is on a front or outer side 244 (facing outwards to reviewers as shown in FIG. 2) of the 3D cavity slot 210, whereas the other five

sides

202, 204, 232, 234, 242 are made of conducting materials.

Among the six sides, a top side 202 and a bottom side 204 are substantially parallel to, or in plane with, the ground planes 222 and 224, respectively. For example, the top side 202 and the bottom side 204 can be two conductive planes formed by parts of the ground planes 222 and 224, respectively. The top side 202 and the bottom side 204 are substantially in parallel with each other and are spaced by a distance, w, which is the width of the slot aperture 250. As shown in FIG. 2, each of the

sides

202 and 204 is a rectangle having a dimension of L x d, where d is the depth of the 3D cavity slot 210.

The 3D cavity slot 210 also has two

lateral sides

232 and 234. The lateral sides 232 and 234 can be two conductive planes made of the same or different materials of the ground planes 222 and 224. The lateral sides 232 and 234 are substantially in parallel with each other and are spaced by a distance, L, which is the length of the slot aperture 250. As shown in FIG. 2, each of the

lateral sides

232 and 234 is a rectangle having a dimension of d x w, where d is the depth of the 3D cavity slot 210.

The 3D cavity slot 210 also has an inner or back side 242 and an outer or front side 244. The inner side 232 can be a conductive plane made of the same or different materials of the ground planes 222 and 224; the outer side 232 is formed by the slot aperture 250. The inner side 242 and outer side 244 are substantially in parallel with each other and are spaced by a distance, d, which is the depth of the 3D cavity slot 210. As shown in FIG. 2, each of the inner side 242 and outer side 244 is a rectangular having a dimension of L x w, where w is the width of the 3D cavity slot 210.

In some implementations, a printed circuit board (PCB) can be used to form such a 3D cavity slot 210 utilizing the PCB’s multi-layer and via structure. For example, the two

ground planes

222 and 224 of the 3D cavity slot 210 can be configured by the PCB’s two layers, and so do the top and

bottom sides

202, 204 of the 3D cavity slot 210. The lateral sides, 232, 234, and the inner side 242 can be configured by the PCB’s substrate integrated waveguide (SIW) vias (shorting walls) . The space between the PCB’s two layers and corresponding vias can define the slot aperture 250.

In some implementations, the 3D cavity slot 210 itself can be used as a cavity slot antenna that has a vertical polarization as shown by the arrows in FIG. 2 (e.g., along the PCB thickness direction) . However, the bandwidth of such a 3D cavity slot antenna is limited. For example, the 3D cavity slot antenna only supports an appropriately 7%bandwidth. For 5G communications over the B257 (26.5～29.5GHz) band, antennas are desirable to support at least 12%of bandwidth.

To support wideband communications in 5G, a wideband vertical polarized (V-pol) antenna can be configured based on the structure of 3D cavity slot 210. In some implementations, both the depth and length of the 3D cavity slot 210 affect resonant frequencies of the wideband V-pol antenna.

FIG. 3 is a schematic diagram illustrating portions of an example wideband vertical polarized (V-pol) antenna 300, according to an implementation. The example wideband V-pol antenna 300 includes two

ground planes

312 and 314 spaced apart in a first dimension (e.g., a vertical or height dimention as indicated by h in FIG. 3) , a 3D cavity slot 310 formed in between the ground planes 312 and 314, and an antenna feed 320 inside the 3D cavity slot 310. The two

ground planes

312 and 314 can be examples of the two

ground planes

222 and 224 described with respect to FIG. 2. For example, the two

ground planes

312 and 314 can be formed by folding a planar metal sheet. The 3D cavity slot 310 can be an example of the 3D cavity slot 210 described with respect to FIG. 2.

The 3D cavity slot 310 has a length of L=λ ₁/2, a width or height of h, and a depth of d. For example, the 3D cavity slot 310 can have a cuboid shape and be defined by six sides or

surfaces

302, 304, 332, 334, 342 and 344, corresponding to the six

sides

202, 204, 232, 234, 242 and 244 of the 3D cavity slot 210, respectively. The 3D cavity slot 310 includes a slot aperture 350 on an outer side 344, whereas the other five sides are made of conducting materials. The slot aperture 350 can be a vertical slot aperture that has a length of L=λ ₁/2 and a width or height of h.

Among the six sides, a top side 302 and a bottom side 304 are substantially in parallel or in plane with the ground planes 312 and 314, respectively. For example, the top side 302 and the bottom side 304 can be two conductive planes formed by parts of the ground planes 312 and 314, respectively. The top side 302 and the bottom side 304 are substantially in parallel with each other and are spaced by a distance, h, which is the width or vertical height of the slot aperture 350. In some implementations, the width or height of h of the slot aperture 350 (and the 3D cavity slot 310) is configured to be less than 1/10 λ _0, to achieve a small vertical profile of wideband V-pol antenna 300. As shown in FIG. 3, each of the

sides

302 and 304 has a dimension of L x d, where L is the length and d is the depth of the 3D cavity slot 310.

The 3D cavity slot 310 also has two

lateral sides

332 and 334. The lateral sides 332 and 334 can be two conductive planes made of the same or different materials of the ground planes 312 and 314. The lateral sides 332 and 334 are substantially in parallel with each other and are spaced by a distance, L, which is the length of the slot aperture 350. As shown in FIG. 3, each of the lateral sides 333 and 334 has a dimension of d x h, where d is the depth of the 3D cavity slot 310.

The 3D cavity slot 310 also has an inner side 342 and an outer side 344. The inner side 342 can be a conductive plane made of the same or different materials of the ground planes 312 and 314; the outer side 344 is formed by the slot aperture 350. The inner side 342 and outer side 344 are substantially in parallel with each other and are spaced by a distance d, which is the depth of the 3D cavity slot 310. As shown in FIG. 3, each of the inner side 342 and outer side 344 has a dimension of L x h, where h is the height of the 3D cavity slot 310.

The example wideband V-pol antenna 300 includes the antenna feed 320 (e.g., a feedline) configured to feed the 3D cavity slot 310 inside the 3D cavity slot 310. The antenna feed 320 is configured to excite a TE10 mode and generate an Electric Field (E-field) along the first dimension at the first resonant frequency f ₁ of the example wideband V-pol antenna 300, resulting in a vertical polarization of the example wideband V-pol antenna 300.

The antenna feed 320 is short circuited to the 3D cavity slot 310 such that the antenna feed 320 and the 3D cavity slot 310 form a closed loop capable of generating a magnetic field around the closed loop that excites an unbalanced TE20 mode inside the 3D cavity slot 310.

In some implementations, the antenna feed 320 can be of a loop shape that includes a horizontal portion 322 along the horizontal or depth dimension of the 3D cavity slot 310 and two

vertical portions

324 and 326 along the vertical or height dimension of the 3D cavity slot 310. In some implementations, the horizontal portion 322 is substantially in parallel with the ground planes 312 and 314, while the vertical portion 324 is substantially vertical to the ground planes 312 and 314, where “substantially” vertical includes vertical or functionally equivalent to being vertical so long as functionality (e.g., structural or electrical functionality) can be maintained. For example, if the vertical portion 324 has an angle within 88～92 degrees relative to the ground planes 312 and 314, the vertical portion 324 is considered substantially vertical to the ground planes 312 and 314.

As shown in FIG. 3, the horizontal portion 322 of the antenna feed 320 is short circuited to one side of the 3D cavity slot 310 (e.g., the inner side 342 of the 3D cavity slot 310) . In some implementations, the horizontal portion 322 of the antenna feed 320 is connected to the inner side 342 of the 3D cavity slot 310 and extends outwards to the outer side 344 as close as to the slot aperture 350. The horizontal portion 322 has a dimension of L ₁ x d ₁, where L ₁ < L and d ₁ <= d. In some implementations, L ₁ is substantially less than L (e.g., less than 1/5 or 1/10 of L) , and d ₁ is substantially equal to d, so that the horizontal portion 322 extends substantially close to the slot aperture 350 on the outer side 344, wherein “substantially equal” includes equal, or slightly greater than or less (e.g., within a tolerance range of 5%or 10%) than, so long as functionality can be maintained, and “substantially close” includes having a short or negligible distance (e.g., the distance is less than 1 or even 0.1 mm, so long as functionality can be maintained.

Between the two

vertical portions

324 and 326, the vertical portion 324 is located closer to the slot aperture 350 on the outer side 344, while the vertical portion 326 is located closer to the inner side 342. In some implementations, the two

vertical portions

324 and 326 are substantially in parallel with each other. One end of each of the two

vertical portions

324 and 326 is short circuited to the horizontal portion 322 of the antenna feed 320, and the other end of each of the two

vertical portions

324 and 326 is short circuited to one side of the 3D cavity slot 310 (e.g., the top side 302 or the bottom side 304) of the 3D cavity slot 310.

For example, In some implementations, one end of the vertical portion 324 extends from, or is connected to the horizontal portion 322, at or near the outer end of the horizontal portion 322 closer to the outer side 344; and one end of the vertical portion 326 extends from, or is connected to, the horizontal portion 322 at or near the inner end of the horizontal portion 322 closer to the inner side 342. As shown in FIG. 3, the other end of the vertical portion 324 and the other end of the vertical portion 324 are both short circuited to the bottom side 304 of the 3D cavity slot 310. In some implementations, the other end of the vertical portion 324 and the other end of the vertical portion 324 can be both short circuited to the top side 302 of the 3D cavity slot 310. In other words, although FIG. 3 shows that the

vertical portions

324 and 326 extend downwards along the height dimension from the horizontal portion 322 towards the bottom side 304, the

vertical portions

324 and 326 can extend upwards along the height dimension from the horizontal portion 322, towards the top side 302 in some other implementations.

In some implementations, the

vertical portions

324 and 326 can have the same or different shape or size. For example, the vertical portion 324 can have a dimension of h ₂ x L ₂, where h ₂ <= h and L ₂ <= L ₁ . The vertical portion 326 can have a dimension of h ₃ x L ₃, where h ₃ <= h and L ₃ <= L ₁ . In some implementations, L ₂ and L ₃ are both substantially equal to L ₁. h ₂ and h ₃ are substantially equal. h ₂ and h ₃ depend on the location of the horizontal portion 322 relative to the top side 302 or the bottom side 304 of the 3D cavity slot 310. For example, if the horizontal portion 322 is spaced by a distance or height of h ₁ from the top side 304, h ₂ = h ₃ = h –h ₁.

In some implementations, the antenna feed 320 can be configured using a coaxial feed or stripline feed with the vertical portion 324 located at, or as close as possible to, the slot aperture 350 of the 3D cavity slot 310 and short circuited to one side (e.g., the top side 302 or the bottom side 304) of the 3D cavity slot 310 to give rise to strong vertical polarization. For example, in some implementations, the

vertical portions

324 and 326 can be constructed by bending or folding the antenna feed 320 upwards or downwards along the height dimension of the 3D cavity slot 310. In some implementations, the antenna feed 320 can be an embedded 50 Ohm CPW line in-between the top side 302 or the bottom side 304 of the 3D cavity slot 310 (also the folded ground planes 312 and 314 in some implementations) and then short circuited to the bottom side 304.

In some implementations, the antenna feed 320 can be configured using one or more layers of a PCB to form the horizontal portion 322 and one or more vias of the PCB to form the

vertical portion

324 and 326. In some implementations, the antenna feed 320 can be configured in another manner. For example, the antenna feed 320 can be configured to have an L shape that includes the horizontal portion 322 and the vertical portion 324, but not the

vertical portions

326 and 326, wherein the horizontal portion 322 and the vertical portion 324 are short circuited to the 3D cavity slot 310 such that the antenna feed 320 and the 3D cavity slot 310 form a closed loop capable of generating a magnetic field around the closed loop that excites an unbalanced TE20 mode inside the 3D cavity slot 310. As an example, in an L-shape configuration, the antenna feed 320 can have the horizontal portion 322 short circuited to the inner side 342 and the vertical portion 324 short circuited to the bottom side 304 of the 3D cavity slot 310 such that the antenna feed 320 and the 3D cavity slot 310 form the closed loop.

In some implementations, the antenna feed 320 feeds the 3D cavity slot 310 of the center of the 3D cavity slot 310. Thus, the antenna feed 320 can be referred to as an offset antenna feed. In some implementations, the location of the antenna feed 320 relative to the

lateral side

332 or 334 of the 3D cavity slot 310 can be configured, for example, to match impedance, to achieve a desired return loss or gain pattern, or for other purposes. As shown in FIG. 3, the antenna feed 320 is λ ₂/4 away from the lateral side 334 of the 3D cavity slot 310, wherein λ ₂ is a wavelength corresponding to a second resonant frequency f ₂ of the example wideband V-pol antenna 300. In some implementations, the antenna feed 320 can be placed in other locations to feed the 3D cavity slot 310.

FIG. 4 is a plot illustrating an example return loss 400 of an example wideband V-pol antenna (e.g., the example wideband V-pol antenna 300) , according to an implementation. The example return loss 400 can be an example result of modal analysis of the example wideband V-pol antenna 300. As shown in FIG. 4, the return losses (or reflection coefficients represented by S11) of the example wideband V-pol antenna 300 at 26.3GHz and 29.9 GHz are both approximately -10dB. As such, the example wideband V-pol antenna 300 has a wide bandwidth and can support the 26.5～29.5 GHz band of the 5G system.

FIG. 5 is a plot illustrating an example Electric Field (E-field) 500 of an example wideband V-pol antenna (e.g., the example wideband V-pol antenna 300) in a TE10 mode, according to an implementation. In this example, the E-field 500 is measured at a first resonance or radiating frequency f ₁ = 26.5 GHz. As illustrated in FIG. 5, the

vertical portions

324 and 326 of the antenna feed 320 excite the TE10 mode. As denoted by the arrows 510, the resulting E-field 500 is vertical and lines up everywhere along the height or width dimension of the slot aperture 350 (also the thickness or height dimension of the 3D cavity slot 310) , giving rise to the vertical polarization of the example wideband V-pol antenna 300.

FIG. 6A is a plot illustrating an example E-field 600 of an example wideband V-pol antenna (e.g., the example wideband V-pol antenna 300) in a TE20 mode, according to an implementation. In this example, the E-field 600 is measured at a second resonance or radiating frequency f ₂ = 29.4 GHz. FIG. 6B is a plot illustrating example magnetic field (H-field) 650 of an example wideband V-pol antenna (e.g., the example wideband V-pol antenna 300) in a TE20 mode, according to an implementation. In this example, the H-filed is measured at 29.4 GHz.

As illustrated in FIG. 6B, the horizontal portion 322 of the antenna feed 320 is short circuited to the inner side 342 of the 3D cavity slot 310 and the

vertical portions

324 and 326 of the antenna feed 320 are short circuited to the bottom side 304 of the 3D cavity slot 310, forming a loop-shape feeding structure. The loop-shape feeding structure is equivalent to a magnetic dipole that generates an H-field 626 around the loop-shape feeding structure that excites an unbalanced TE20 mode inside of the 3D cavity slot 310, as shown in FIG. 6A.

Compared to a typical balanced TE20 mode that has approximately

equal E-fields

602 and 604 with opposite directions as shown in FIG. 6C, the unbalanced TE20 mode as shown in FIG. 6A has a stronger E-field 620 at one side where the antenna feed 320 is located and a weaker E-field 610 at the other side. Both the stronger E-field 620 and the weaker E-field 610 are vertical but of different directions. Because of the unbalance, the stronger E-field 620 contributes mainly to the radiation and raises a strong vertical polarization with end-fire coverage, and its radiation pattern still has one main beam with good linearity as shown in FIGS. 11A-11B and 12A-12B below.

FIG. 7A is a plot illustrating an example E-field 700 of an example wideband V-pol antenna (e.g., the example wideband V-pol antenna 300) in the TE10 mode, according to an implementation. In this example, the E-field 500 is measured at the first resonance or radiating frequency f ₁ = 26.5 GHz. FIG. 7B is a plot illustrating an example E-field 730 of the example wideband V-pol antenna 300 in the unbalanced TE20 mode, according to an implementation. In this example, the E-filed is measured a second resonance or radiating frequency f ₂ = 29.5 GHz.

FIG. 7C is a plot illustrating an example H-field 760 of the example wideband V-pol antenna 300 in the TE10 mode, according to an implementation. In this example, the E-field 500 is measured at the first resonance or radiating frequency f ₁ = 26.5 GHz. FIG. 7D is a plot illustrating an example H-field 790 of the example wideband V-pol antenna 300 in the unbalanced TE20 mode, according to an implementation. In this example, the E-filed is measured at the second resonance or radiating frequency f ₂ = 29.5 GHz.

FIG. 8A is a schematic diagram illustrating portions of another example 3D slot antenna 800, according to an implementation. The example 3D slot antenna 800 includes two

ground planes

812 and 814, a 3D cavity slot 810 form between the ground planes 812 and 814, and an antenna feed 820 inside the 3D cavity slot 810. The 3D cavity slot 810 can have the same structure as the 3D cavity slot 310 of the example wideband V-pol antenna 300. The antenna feed 820 is a probe feed that short circuited to the ground planes 812 and 814. The antenna feed 820 can be offset and have a distance of feed_x relative to a lateral side 834 of the 3D cavity slot 810. However, unlike the antenna feed 320 of the example wideband V-pol antenna 300 that forms a loop-shape feeding structure (e.g., by the L-shaped antenna feed 320) that results in an unbalanced TE20 mode, the probe antenna feed 820 does not generate a 2 ^nd resonance frequency to achieve a wide bandwidth of the example 3D slot antenna 800.

FIG. 8B is a plot illustrating an example return loss 850 of the another example 3D slot antenna 800, according to an implementation. The example return loss 850 shows that, even with different offset distances of feed_x, the shorted probe antenna feed 820 does not generate the 2nd resonance. Accordingly, the example 3D slot antenna 800 does not have a wide bandwidth to support wide-band communications over the 26.5～29.5 GHz band of the 5G system.

FIG. 9A is a schematic diagram illustrating portions of yet another example 3D slot antenna 900, according to an implementation. The example 3D slot antenna 900 includes two

ground planes

912 and 914, a 3D cavity slot 910 form between the ground planes 912 and 914, and an antenna feed 920 inside the 3D cavity slot 910. The 3D cavity slot 910 can have the same structure as the 3D cavity slot 310 of the example wideband V-pol antenna 300. The antenna feed 920 is an open-ended L-shaped probe feed that is not short circuited or otherwise connected to either of the ground planes 912 and 914, nor an inner side 942 of the 3D cavity slot 910. The antenna feed 920 can be offset and have a distance of feed_x relative to a lateral side 934 of the 3D cavity slot 910 However, unlike the antenna feed 320 of the example wideband V-pol antenna 300 that is closed-ended because both ends of the antenna feed 320 are short circuited or otherwise connected to the inner side 342 and bottom side 304 of the 3D cavity slot 310 (also the ground planes 312 and 314) , respectively, the open-ended L-shaped probe antenna feed 920 does not generate a 2 ^nd resonance frequency to achieve a wide bandwidth of the example 3D slot antenna 900.

FIG. 9B is a plot illustrating an example return loss 950 of the yet another example 3D slot antenna 900, according to an implementation. The example return loss 950 shows that, even with different offset distances of feed_x, the open-ended L-shaped probe antenna feed 920 does not generate the 2nd resonance. Accordingly, the example 3D slot antenna 900 does not have a wide bandwidth to support wide-band communications over the 26.5～29.5 GHz band of the 5G system.

FIGS. 10A-10B are plots illustrating gain patterns of the example wideband V-pol antenna 300, according to an implementation. Specifically, FIG. 10A illustrates the gain pattern 1000 of the example wideband V-pol antenna 300 at 26.5 GHz due to the TE10 mode. The main lobe direction (the maximum gain direction) 1010 is at Theta = 92° and Phi = 84°, which is substantially pointing to the vertical direction (i.e., the z-axis as shown in FIG. 10A) . As illustrated in FIG. 10A, the vertical direction is the height or thickness dimension of the example wideband V-pol antenna 300, which is perpendicular to the ground planes 312 and 314 spanned by the x-axis and y-axis.

FIG. 10B shows the gain pattern 1050 of the example wideband V-pol antenna 300 at 29.5 GHz due to the unbalanced TE20 mode. The main lobe direction (the maximum gain direction) 1015 is at Theta = 102° and Phi = 74° , which is tilted slightly away from the vertical direction (i.e., the z-axis as shown in FIG. 10B) .

FIGS. 11A-11B are

plots

1100 and 1150 illustrating gain vs. angle patterns of the example wideband V-pol antenna 300 in E and H-planes at the 1 ^st resonance frequency, respectively, according to an implementation. Specifically, FIG. 11A illustrates the E-plane co-polarization (co-pol) 1110 and cross-polarization (x-pol) 1120 of the example wideband V-pol antenna 300 at the 1 ^st resonance frequency of 26.5 GHz and Phi = 90°. FIG. 11B illustrates the H-plane co-polarization (co-pol) 1130 and cross-polarization (x-pol) 1140 of the example wideband V-pol antenna 300 at 26.5 GHz and Phi = 90°. Low cross-polarization in both E and H-planes means the example wideband V-pol antenna 300 provides good linearity at the 1 ^st resonance frequency of 26.5 GHz.

FIGS. 12A-12B are plots 1200 and 1250illustrating gain vs. angle patterns of the example wideband V-pol antenna in E and H-planes at the 2 ^nd resonance frequency, respectively, according to an implementation. Specifically, FIG. 12A illustrates the E-plane co-polarization (co-pol) 1210 and cross-polarization (x-pol) 1220 of the example wideband V-pol antenna 300 at the 2 ^nd resonance frequency of 29.5 GHz and Phi = 90°. FIG. 12B illustrates the H-plane co-polarization (co-pol) 1230 and cross-polarization (x-pol) 1240 of the example wideband V-pol antenna 300 at 29.5 GHz and Phi = 90°. Low cross-polarization in both E and H-planes means the example wideband V-pol antenna 300 provides good linearity at the 2 ^nd resonance frequency of 29.5 GHz.

FIG. 13 is a plot illustrating an example array gain 1300 of an example wideband V-pol antenna array, according to an implementation. The example wideband V-pol antenna array includes four of the example wideband V-pol antenna 300. The example array gain 1300 shows that the maximum gain direction 1310 is aligned with the y-axis direction, i.e., Phi = 90° direction.

Implementations of the subject matter and the functional operations described in this specification can be implemented in digital electronic circuitry, in tangibly embodied computer software or firmware, in computer hardware, including the structures disclosed in this specification and their structural equivalents, or in combinations of one or more of them. Implementations of the subject matter described in this specification can be implemented as one or more computer programs, that is, one or more modules of computer program instructions encoded on a tangible, non-transitory, computer-readable computer-storage medium for execution by, or to control the operation of, data processing apparatus. Alternatively, or additionally, the program instructions can be encoded in/on an artificially generated propagated signal, for example, a machine-generated electrical, optical, or electromagnetic signal that is generated to encode information for transmission to suitable receiver apparatus for execution by a data processing apparatus. The computer-storage medium can be a machine-readable storage device, a machine-readable storage substrate, a random or serial access memory device, or a combination of computer-storage mediums.

The terms “data processing apparatus, ” “computer, ” or “electronic computer device” (or equivalent as understood by one of ordinary skill in the art) refer to data processing hardware and encompass all kinds of apparatus, devices, and machines for processing data, including by way of example, a programmable processor, a computer, or multiple processors or computers. The apparatus can also be or further include special purpose logic circuitry, for example, a central processing unit (CPU) , an FPGA (field programmable gate array) , or an ASIC (application-specific integrated circuit) . In some implementations, the data processing apparatus or special purpose logic circuitry (or a combination of the data processing apparatus or special purpose logic circuitry) may be hardware-or software-based (or a combination of both hardware-and software-based) . The apparatus can optionally include code that creates an execution environment for computer programs, for example, code that constitutes processor firmware, a protocol stack, a database management system, an operating system, or a combination of execution environments. The present disclosure contemplates the use of data processing apparatuses with or without conventional operating systems, for example LINUX, UNIX, WINDOWS, MAC OS, ANDROID, IOS, or any other suitable conventional operating system.

A computer program, which may also be referred to or described as a program, software, a software application, a module, a software module, a script, or code can be written in any form of programming language, including compiled or interpreted languages, or declarative or procedural languages, and it can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program may, but need not, correspond to a file in a file system. A program can be stored in a portion of a file that holds other programs or data, for example, one or more scripts stored in a markup language document, in a single file dedicated to the program in question, or in multiple coordinated files, for example, files that store one or more modules, sub-programs, or portions of code. A computer program can be deployed to be executed on one computer or on multiple computers that are located at one site or distributed across multiple sites and interconnected by a communication network. While portions of the programs illustrated in the various figures are shown as individual modules that implement the various features and functionality through various objects, methods, or other processes, the programs may instead include a number of sub-modules, third-party services, components, libraries, and such, as appropriate. Conversely, the features and functionality of various components can be combined into single components, as appropriate. Thresholds used to make computational determinations can be statically, dynamically, or both statically and dynamically determined.

The methods, processes, or logic flows described in this specification can be performed by one or more programmable computers that execute one or more computer programs to perform functions by operating on input data and generating output. The methods, processes, or logic flows can also be performed by, and apparatus can also be implemented as, special purpose logic circuitry, for example, a CPU, an FPGA, or an ASIC.

Computers suitable for the execution of a computer program can be based on general or special purpose microprocessors, both, or any other kind of CPU. Generally, a CPU will receive instructions and data from a read-only memory (ROM) or a random access memory (RAM) , or both. The elements of a computer include a CPU, for performing or that execute instructions, and one or more memory devices for storing instructions and data. Generally, a computer will also include, or be operatively coupled to, receive data from or transfer data to, or both, one or more mass storage devices for storing data, for example, magnetic, magneto-optical disks, or optical disks. However, a computer need not have such devices. Moreover, a computer can be embedded in another device, for example, a mobile telephone, a personal digital assistant (PDA) , a mobile audio or video player, a game console, a global positioning system (GPS) receiver, or a portable storage device, for example, a universal serial bus (USB) flash drive, to name just a few.

Computer-readable media (transitory or non-transitory, as appropriate) suitable for storing computer program instructions and data includes all forms of non-volatile memory, media, and memory devices, including by way of example semiconductor memory devices, for example, erasable programmable read-only memory (EPROM) , electrically erasable programmable read-only memory (EEPROM) , and flash memory devices; magnetic disks, for example, internal hard disks or removable disks; magneto-optical disks; and CD-ROM, DVD+/-R, DVD-RAM, and DVD-ROM disks. The memory may store various objects or data, including caches, classes, frameworks, applications, backup data, jobs, web pages, web page templates, database tables, repositories storing dynamic information, and any other appropriate information including any parameters, variables, algorithms, instructions, rules, constraints, or references thereto. Additionally, the memory may include any other appropriate data, such as logs, policies, security or access data, reporting files, as well as others. The processor and the memory can be supplemented by, or incorporated in, special purpose logic circuitry.

To provide for interaction with a user, implementations of the subject matter described in this specification can be implemented on a computer having a display device, for example, a CRT (cathode ray tube) , LCD (liquid crystal display) , LED (Light Emitting Diode) , or plasma monitor, for displaying information to the user and a keyboard and a pointing device, for example, a mouse, trackball, or trackpad by which the user can provide input to the computer. Input may also be provided to the computer using a touchscreen, such as a tablet computer surface with pressure sensitivity, a multi-touch screen using capacitive or electric sensing, or other type of touchscreen. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback, for example, visual feedback, auditory feedback, or tactile feedback; and input from the user can be received in any form, including acoustic, speech, or tactile input. In addition, a computer can interact with a user by sending documents to and receiving documents from a device that is used by the user; for example, by sending web pages to a web browser on a user’s client device in response to requests received from the web browser.

The term “graphical user interface, ” or “GUI, ” may be used in the singular or the plural to describe one or more graphical user interfaces and each of the displays of a particular graphical user interface. Therefore, a GUI may represent any graphical user interface, including but not limited to, a web browser, a touch screen, or a command line interface (CLI) that processes information and efficiently presents the information results to the user. In general, a GUI may include a number of user interface (UI) elements, some or all associated with a web browser, such as interactive fields, pull-down lists, and buttons. These and other UI elements may be related to or represent the functions of the web browser.

Implementations of the subject matter described in this specification can be implemented in a computing system that includes a back-end component, for example, as a data server, or that includes a middleware component, for example, an application server, or that includes a front-end component, for example, a client computer having a graphical user interface or a Web browser through which a user can interact with an implementation of the subject matter described in this specification, or any combination of one or more such back-end, middleware, or front-end components. The components of the system can be interconnected by any form or medium of wireline or wireless digital data communication (or a combination of data communication) , for example, a communication network. Examples of communication networks include a local area network (LAN) , a radio access network (RAN) , a metropolitan area network (MAN) , a wide area network (WAN) , Worldwide Interoperability for Microwave Access (WIMAX) , a wireless local area network (WLAN) using, for example, 802.11 a/b/g/n or 802.20 (or a combination of 802.11x and 802.20 or other protocols consistent with this disclosure) , all or a portion of the Internet, or any other communication system or systems at one or more locations (or a combination of communication networks) . The network may communicate with, for example, Internet Protocol (IP) packets, Frame Relay frames, Asynchronous Transfer Mode (ATM) cells, voice, video, data, or other suitable information (or a combination of communication types) between network addresses.

The computing system can include clients and servers. A client and server are generally remote from each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other.

While this specification contains many specific implementation details, these should not be construed as limitations on the scope of any invention or on the scope of what may be claimed, but rather as descriptions of features that may be specific to particular implementations of particular inventions. Certain features that are described in this specification in the context of separate implementations can also be implemented, in combination, in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations, separately, or in any suitable sub-combination. Moreover, although previously described features may be described as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can, in some cases, be excised from the combination, and the claimed combination may be directed to a sub-combination or variation of a sub-combination.

Particular implementations of the subject matter have been described. Other implementations, alterations, and permutations of the described implementations are within the scope of the following claims as will be apparent to those skilled in the art. While operations are depicted in the drawings or claims in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed (some operations may be considered optional) , to achieve desirable results. In certain circumstances, multitasking or parallel processing (or a combination of multitasking and parallel processing) may be advantageous and performed as deemed appropriate.

Moreover, the separation or integration of various system modules and components in the previously described implementations should not be understood as requiring such separation or integration in all implementations, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products.

Accordingly, the previously described example implementations do not define or constrain this disclosure. Other changes, substitutions, and alterations are also possible without departing from the spirit and scope of this disclosure.

Furthermore, any claimed implementation is considered to be applicable to at least a computer-implemented method; a non-transitory, computer-readable medium storing computer-readable instructions to perform the computer-implemented method; and a computer system including a computer memory interoperably coupled with a hardware processor configured to perform the computer-implemented method or the instructions stored on the non-transitory, computer-readable medium.

Claims

An antenna comprising:

two ground planes spaced apart in a first dimension;

a three-dimensional (3D) cavity slot in between the two ground planes, wherein the 3D cavity slot comprises an aperture in the first dimension; and

an antenna feed configured to feed the antenna inside the 3D cavity slot, wherein the antenna feed is short circuited to the 3D cavity slot, and the antenna feed and the 3D cavity slot form a closed loop capable of generating a magnetic field around the closed loop that excites an unbalanced TE20 mode inside the 3D cavity slot.
The antenna of claim 1, wherein the antenna feed comprises a loop-shape antenna feed.
The antenna of claim 2, wherein the loop-shape antenna feed comprises:

a first portion substantially in parellel with at least one of the two ground planes; and

a second portion substantially vertical to one of the two ground planes; and

a third portion substantially vertical to one of the two ground planes, wherein the second portion is closer to the aperture than the third portion.
The antenna of claim 3, wherein the second portion is substantially close to the aperture.
The antenna of any one of claims 1-4, wherein the aperture is of a length of λ ₁/2, wherein λ ₁ is a wavelength corresponding to a first resonant frequency f ₁ of the antenna.
The antenna of claim 5, wherein the antenna feed excites a TE10 mode and generates an E-field along the first dimension at the first resonant frequency f ₁ of the antenna, resulting in a vertical polarization of the antenna.
The antenna of claim 5, wherein the aperture is of a width of w, wherein w is substantially less than λ ₁/10.
The antenna of any one of claims 1-7, wherein the antenna feed is λ ₂/4 away from one end of the aperture, wherein λ ₂ is a wavelength corresponding to a second resonant frequency f ₂ of the antenna.
The antenna of any one of claims 1-8, wherein the two ground planes are formed by a first layer and a second layer of a printed circuit board (PCB) , and the antenna feed is formed by a third or more layers and one or more vias of the PCB.
The antenna of claim 8, wherein the antenna has a vertical polarization along the first dimension, and the first dimension is a thickness dimension of the PCB.
A wireless apparatus comprising:

an antenna comprising:

two ground planes spaced apart in a first dimension;

a three-dimensional (3D) cavity slot in between the two ground planes, wherein the 3D cavity slot comprises an aperture in the first dimension; and

an antenna feed configured to feed the antenna inside the 3D cavity slot, wherein the antenna feed is short circuited to the 3D cavity slot, and the antenna feed and the 3D cavity slot form a closed loop capable of generating a magnetic field around the closed loop that excites an unbalanced TE20 mode inside the 3D cavity slot.
The wireless apparatus of claim 11, wherein the antenna feed comprises a loop-shape antenna feed.
The wireless apparatus of claim 12, wherein the loop-shape antenna feed comprises:

a first portion substantially in parellel with at least one of the two ground planes; and

a second portion substantially vertical to one of the two ground planes; and

a third portion substantially vertical to one of the two ground planes, wherein the second portion is closer to the aperture than the third portion.
The wireless apparatus of claim 13, wherein the second portion is substantially
The wireless apparatus of any one of claims 11-14, wherein the aperture is of a length of λ ₁/2, wherein λ ₁ is a wavelength corresponding to a first resonant frequency f ₁ of the antenna.
The wireless apparatus of claim 15, wherein the antenna feed excites a TE10 mode and generates an E-field along the first dimension at the first resonant frequency f ₁ of the antenna, resulting in a vertical polarization of the antenna.
The wireless apparatus of claim 15, wherein the aperture is of a width of w, wherein w is substantially less than λ ₁/10.
The wireless apparatus of any one of claims 11-17, wherein the antenna feed is λ ₂/4 away from one end of the aperture, wherein λ ₂ is a wavelength corresponding to a second resonant frequency f ₂ of the antenna.
The wireless apparatus of any one of claims 11-18, wherein the two ground planes are formed by a first layer and a second layer of a printed circuit board (PCB) , and the antenna feed is formed by a third or more layers and one or more vias of the PCB.
The wireless apparatus of claim 19, wherein the antenna has a vertical polarization along the first dimension, and the first dimension is a thickness dimension of the PCB.
An antenna array comprising:

a plurality of antennas, wherein each antenna comprising:

two ground planes spaced apart in a first dimension;

a three-dimensional (3D) cavity slot in between the two ground planes, wherein the 3D cavity slot comprises an aperture in the first dimension; and

an antenna feed configured to feed the antenna inside the 3D cavity slot, wherein the antenna feed is short circuited to the 3D cavity slot, and the antenna feed and the 3D cavity slot form a closed loop capable of generating a magnetic field around the closed loop that excites an unbalanced TE20 mode inside the 3D cavity slot.
The antenna array of claim 21, wherein the antenna feed comprises a loop-shape antenna feed.
The antenna array of claim 22, wherein the loop-shape antenna feed comprises:

a first portion substantially in parellel with at least one of the two ground planes; and

a second portion substantially vertical to one of the two ground planes; and

a third portion substantially vertical to one of the two ground planes, wherein the second portion is closer to the aperture than the third portion.
The antenna array of claim 23, wherein the second portion is substantially close to the aperture.
The antenna array of any one of claims 21-24, wherein the aperture is of a length of λ ₁/2, wherein λ ₁ is a wavelength corresponding to a first resonant frequency f ₁ of the antenna.
The antenna array of claim 25, wherein the antenna feed excites a TE10 mode and generates an E-field along the first dimension at the first resonant frequency f ₁ of the antenna, resulting in a vertical polarization of the antenna.
The antenna array of claim 25, wherein the aperture is of a width of w, wherein w is substantially less than λ ₁/10.
The antenna array of any one of claims 21-27, wherein the antenna feed is λ ₂/4 away from one end of the aperture, wherein λ ₂ is a wavelength corresponding to a second resonant frequency f ₂ of the antenna.
The antenna array of any one of claims 21-28, wherein the two ground planes are formed by a first layer and a second layer of a printed circuit board (PCB) , and the antenna feed is formed by a third or more layers and one or more vias of the PCB.
The antenna array of claim 29, wherein the each antenna has a vertical polarization along the first dimension, and the first dimension is a thickness dimension of the PCB.