WO2023217236A1

WO2023217236A1 - Antenna unit, subarray and millimeter-wave high-isolation large-angle phased array antenna

Info

Publication number: WO2023217236A1
Application number: PCT/CN2023/093550
Authority: WO
Inventors: 杨琬琛; 刘宇济; 车文荃; 薛泉; 刘旭夫; 冯文杰; 朱浩慎
Original assignee: 华南理工大学
Priority date: 2022-05-12
Filing date: 2023-05-11
Publication date: 2023-11-16
Also published as: CN114914687A

Abstract

Disclosed in the present invention are an antenna unit, a subarray and a millimeter-wave high-isolation large-angle phased array antenna. The antenna unit comprises a first dielectric substrate, a first metal plate, a second dielectric substrate and a second metal plate, which are tightly attached from top to bottom, wherein a radiation metal patch is arranged on an upper surface of the first dielectric substrate; the first metal plate is connected to the second metal plate by means of metal columns, so as to form a dielectric cavity structure; and a coaxial line excites the radiation metal patch by means of a feed point which is arranged on the second metal plate. Some non-excited metal patches are added to a scanning surface of the phased array antenna, thereby improving the scanning capability of a phased array. The present invention can be easily machined, has a low cost and a low profile, is suitable for planar antenna array design, and is applied to mass production.

Description

An antenna unit, sub-array and millimeter-wave high-isolation large-angle phased array antenna

Technical field

The invention relates to the field of communications, and in particular to an antenna unit, a sub-array and a millimeter-wave high-isolation large-angle phased array antenna.

Background technique

In recent years, with the large-scale commercialization of 5G mobile communication technology, research on 6G communication, the next generation mobile communication technology, has also begun. 6G is like a huge distributed neural network, integrating communication, perception, computing and other capabilities. It deeply integrates the physical world, the biological world and the digital world, truly opening up a new era of "intelligent connectivity of all things". On the basis of 5G, 6G will transcend the Internet of People, the Internet of Things, and move toward the Intelligent Internet of Everything, bringing technology to every person, every family, and every enterprise, leading a new wave of innovation.

In the future, 6G communications will use the millimeter wave frequency band (66-76GHz). However, the path loss of radio waves in the millimeter wave band is large and scattering is limited. Phased array is the key technology to solve this problem. However, millimeter-wave phased array antennas face problems such as narrow beam scanning range and serious deterioration of radiation performance during wide-angle scanning. Traditional array antennas are not only large in size and have high coupling between ports, but also scan beams within a ±50° range. , there will be a gain drop of up to 4-5dBi. Therefore, designing a phased array antenna with wide beam scanning function and high efficiency is very important for 6G communications.

Contents of the invention

In order to overcome the shortcomings and deficiencies of the existing technology, the present invention provides an antenna unit, a sub-array and a millimeter-wave high-isolation large-angle phased array antenna.

The invention not only has the characteristics of small size and simple structure, but also ensures that the millimeter wave array can achieve high isolation, low active return loss, large-angle scanning and other performances.

The present invention adopts the following technical solutions:

An antenna unit includes a first dielectric substrate, a first metal plate, a second dielectric substrate and a second metal plate arranged in close contact from top to bottom. A radiation metal patch is provided on the upper surface of the first dielectric substrate. The first metal plate is connected to the second metal plate through metal pillars to form a dielectric cavity structure, and the coaxial line excites the radiation metal patch through the feed point provided on the second metal plate.

Further, the coaxial line passes through the feed point and excites the radiation metal patch through an L-shaped probe or gap.

Further, the L-shaped probe or slit is provided on the first metal plate and is on the same layer.

A sub-array includes 1×D antenna units and uses a one-D integrated waveguide feed network to excite and radiate metal patches.

Further, the one-to-D integrated waveguide feed network includes at least two one-to-two power splitters, each one-to-two power splitter is arranged on the dielectric substrate and is located between two layers of metal plates.

Further, the metal plate is provided with a signal via hole, and the signal via hole includes a metal pillar and a circular metal patch.

Further, the one-minute D integrated waveguide feed network is surrounded by a circle of metal columns.

A millimeter-wave high-isolation large-angle phased array antenna, which consists of N sub-arrays to form an N×D antenna unit array. The distance between the antenna units on the vertical surface of the antenna is set to 0.38λ, and decoupling is provided between the two antenna units on the vertical surface of the antenna. The structure is on the same layer as the radiating metal patches, and the spacing is 0.38λ; metal patches are provided at the upper and lower ends of the vertical plane of the antenna, on the same layer as the radiating metal patches, and the spacing is 0.38λ, where λ is the center frequency of the antenna. Free space wavelength.

Further, the decoupling structure includes a U-shaped grounding branch.

Further, the metal patch is a metasurface unit, a square patch, a rectangular patch, a parallelogram patch or a trapezoidal patch.

Beneficial effects of the present invention:

(1) The present invention effectively expands the beam width of the antenna and improves the isolation between ports by loading a dielectric cavity structure.

(2) The present invention achieves a high broadband isolation effect by using the coupling path offset method and loading the ground structure, and improves the active return loss and array scanning capability within the operating frequency band.

(3) The present invention effectively improves the scanning performance of the phased array by adding some non-excited metal patches to the scanning surface.

(4) The size of the antenna unit of the present invention is only 0.15λ, and the array spacing of the scanning surface is only 0.38λ, which effectively improves the scanning capability of the antenna, and the antenna occupies a small area.

(5) The present invention reduces energy leakage by adding a circle of metal pillars outside the feed network, and the phase and amplitude of each port of the feed network can be kept consistent.

(6) The present invention has a simple structure, easy processing and relatively low cost. This enables mass production.

Description of the drawings

Figure 1(a) is a three-dimensional schematic diagram of the unit structure of the phased array antenna of the present invention;

Figure 1(b) is a top view of the unit structure of the phased array antenna of the present invention;

Figure 1(c) is a left view of the unit structure of the phased array antenna of the present invention;

Figure 2 is a three-dimensional schematic diagram of the 1×4 sub-array of the phased array antenna of the present invention;

Figure 3(a) is a surface schematic diagram of the phased array antenna of the present invention;

Figure 3(b) is a schematic diagram of the first-stage one-to-two power splitter layer of the phased array antenna of the present invention;

Figure 3(c) is a schematic diagram of the second-stage one-to-two power splitter layer of the phased array antenna of the present invention;

Figure 3(d) is a schematic diagram of the bottom feed of the phased array antenna of the present invention;

Figure 3(e) is a left view of the phased array antenna of the present invention;

Figure 4(a) is the S-parameter result diagram after decoupling of the phased array antenna in Embodiment 3 of the present invention;

Figure 4(b) is an S-parameter result diagram before decoupling of the phased array antenna in Embodiment 3 of the present invention;

Figure 5 is a result diagram of the phased array antenna scanning to 63° at 66GHz in Embodiment 3 of the present invention;

Figure 6 is a result diagram of the phased array antenna scanning from 71 GHz to 62° in Embodiment 3 of the present invention;

Figure 7 is a result diagram of the phased array antenna scanning to 64° at 76GHz in Embodiment 3 of the present invention;

Figure 8 is an active return loss diagram of the phased array antenna during maximum angle scanning in Embodiment 3 of the present invention.

Detailed ways

The present invention will be further described in detail below with reference to the examples and drawings, but the implementation of the present invention is not limited thereto.

Example 1

As shown in Figure 1(a)-Figure 1(c), an antenna unit that constitutes a phased array with high isolation and large scanning angle is processed using low-temperature co-fired ceramic technology, and the dielectric substrate is Ferro A6ME. The first dielectric substrate 6, the first metal plate 15, the second dielectric substrate 7 and the second metal plate 16 are arranged in close contact from top to bottom.

Specifically, a radiation metal patch is provided on the upper surface of the first dielectric substrate 6. The shape of the radiation metal patch is a square patch 1, specifically a square. Other shapes such as a circle, a parallelogram or a rectangular corner can also be selected. structure.

The first metal plate 15 is etched with a square opening, and the metal pillar 3 passes through the square opening to connect the first metal plate 15 and the second metal plate 16 to form a dielectric cavity structure 4 . The feed point of the antenna unit is set on the second metal plate 16. By connecting the coaxial line 5, the square patch 1 is excited through the L-shaped probe 2 or the gap. The L-shaped probe 2 and the first metal plate 15 are arranged on the first metal plate and are on the same layer.

The radiation metal patch is a square patch, its size P_x is 0.64mm, the L-shaped probe is a rectangular metal, its size F_x is 0.52mm, its size F_y is 0.15mm, the dielectric cavity is square, its size C_x1 is 1.6mm, the distance F_l from the L-shaped probe to the medium cavity is 0.44mm, the diameter of the cylindrical metal pillar is 0.1mm, and the center distance Pitch is 0.3mm. The dielectric substrate used is Ferro A6ME, the height H1 of the first dielectric substrate is 0.188mm, the height H2 of the second dielectric substrate is 0.188mm, and the metal conductive band thickness is both 0.008mm.

The size of the antenna unit is only 0.15λ, which can be arranged at a compact spacing. The spacing between the scanning plane (E plane) does not exceed 0.38λ, which is reduced to 76% of the conventional spacing, which is conducive to realizing large-angle scanning, where λ is the center frequency of the antenna. Free space wavelength.

Example 2

As shown in Figure 2, a sub-array constituting a millimeter-wave high-isolation large-scan angle phased array antenna includes 1×4 antenna units and is fed by an integrated waveguide feed network.

The sub-array in this embodiment 2 includes a third dielectric substrate 8, a third metal plate 17, a fourth dielectric substrate 9, a fourth metal plate 18, a fifth dielectric substrate 10 and a fifth metal plate 19 arranged closely together. The waveguide opening 22 is an excitation point and is arranged between the fifth metal plate 19 and the fourth metal plate 18 . 1×4 antenna units are arranged on the upper surface of the third dielectric substrate, and a one-to-four integrated waveguide feed network is used to connect the L-shaped probe through the signal via hole on the second metal plate 16, so that the L-shaped probe excites the surface. Radiating metal patches produce polarized radiation characteristics.

Specifically, the one-to-four integrated waveguide feed network includes two-stage one-to-two power dividers, and the second-stage one-to-two power divider 12 is connected through the signal via on the fourth metal floor 18. The second-stage one-to-two power divider 12 The 2-power splitter 12 is disposed between the fourth dielectric substrate 9 , the fourth metal floor 18 and the third metal floor 17 , and is connected to the first-stage 1-2 power splitter 11 through the signal via on the third metal floor 17 , the first-stage one-to-two power splitter 11 is arranged between the third dielectric substrate 8, the third metal floor 17 and the second metal floor 16, and is connected to the L probe through the signal via on the second metal floor 16. needle, so that the L-shaped probe excites the square metal patch on the surface to produce polarized radiation characteristics.

The one-to-four integrated waveguide feed network can be replaced by a microstrip feed network or a coplanar waveguide feed network.

The signal via hole is composed of a metal pillar and a circular metal patch 13, and its function is to transmit energy. The signal via hole can be replaced by etching a rectangular gap in the metal floor.

In addition, when the subarray includes 1×D antenna units, a one-D integrated waveguide feed network needs to be used to excite the radiation metal patch.

The one-to-D integrated waveguide feed network includes at least two one-to-two power dividers, each one-to-two power divider is arranged on a dielectric substrate, which is located between two layers of metal plates, and the antenna unit is arranged at the most On the upper surface of the upper dielectric substrate, each stage of one-to-two power splitter has signal via holes to transmit energy through the metal plate.

In addition, in order to better realize this embodiment, a circle of metal pillars is added outside the one-to-four integrated waveguide feed network, which can effectively reduce energy leakage and improve the radiation efficiency of the antenna.

Example 3

As shown in Figure 3(a)-Figure 3(e), a millimeter-wave high-isolation large-angle phased array antenna includes N sub-arrays to form an N×D antenna element array. In this embodiment 3, a 4×4 antenna array is composed of four 1×4 sub-array antennas. The distance between the antenna units on the vertical plane (E plane) of the antenna is set to 0.38λ, which helps to improve the scanning performance of the antenna and reduce the size of the antenna array. total measurement.

The phased array adds a decoupling structure on the E side, and the height is consistent with the height of the radiation metal patch 1 without adding additional layers. The decoupling structure includes a U-shaped grounding branch 20 and two metal columns, U The U-shaped ground branch is on the same layer as the antenna unit, and the metal pillar connects the second metal floor 16 and the U-shaped ground branch. The structure is simple without increasing the height and number of layers of the antenna, and can improve large-angle scanning performance.

The antenna array adds a non-excited square metal patch 14 on the vertical plane. The height is consistent with the height of the radiating metal patch. The distance between the radiating metal patch and the radiating metal patch is 0.38λ. It is mainly installed on the vertical plane of the phased array antenna. The top and bottom. After the antenna array is formed, due to the small distance between the units, the dielectric cavities of the units are merged into a large dielectric cavity. A circle of metal pillars 21 is added to the periphery of the integrated waveguide feed network of the antenna, which can effectively reduce the Energy leakage improves the radiation efficiency of the antenna.

The unexcited square metal patch may include an ordinary patch or a metasurface unit, and the shape of the metal patch may be a square, a rectangle, a parallelogram, a trapezoid, etc.

Specifically, arranging the metal patch outside the radiating metal patch on the scanning surface can effectively improve the scanning performance of the antenna and reduce the gain fluctuation during large-angle scanning of the antenna. The scanning capability within the band is greater than ±62°, and the gain decreases. Less than 2dB.

In this embodiment, there are eight metal patches in total, which are specifically square. Four are arranged at the upper end of the phased array antenna scanning surface in the vertical direction, and four are arranged at the lower end, and they are arranged symmetrically.

The U-shaped ground branch 20 can improve the isolation between ports and improve the active callback loss during antenna scanning, and the shape of the ground structure can be U-shaped, C-shaped, Π-shaped, n-shaped, etc.

The horizontal unit spacing y_array of the phased array is 2.32mm, the vertical unit spacing x_array is 1.6mm, the Co_y of the U-shaped ground branch is 0.3mm, Co_x is 0.5mm, the dielectric cavity structure of the phased array Ca_y is 1.7mm, Ca_x is 6.5 mm, the S_y1 of the first-stage one-to-two power divider is 3.42mm, S_x1 is 1.3mm, the S_y2 of the second-stage one-to-two power divider is 5.74mm; the second metal floor, the third metal floor and the fourth metal floor The diameter of the signal vias on the floor is all 0.4mm, and the height h3 of the waveguide feed part, the first-stage one-to-two power splitter, and the second-stage one-to-two power splitter are all 0.376mm.

The size of the antenna unit is only 0.15λ and can be arranged at a compact spacing. The spacing between the scanning plane (E plane) does not exceed 0.38λ, reduced to 76% of the conventional spacing, which is conducive to realizing large-angle scanning, where λ is the free space wavelength of the antenna center frequency.

As shown in Figure 4(a), the millimeter wave high isolation large scanning angle phased array antenna has an operating bandwidth of 66-76GHz, the in-band port reflection coefficient is lower than -10dB, and its in-band isolation is greater than 20dB. Compared with traditional Array antennas have a more compact array arrangement and higher port isolation. As shown in Figure 4(b), the isolation when no U-shaped grounding branches are loaded is above 15dB. By comparison, it is found that the port isolation increases by 5dB after loading U-shaped grounding branches.

As shown in Figure 5, Figure 6 and Figure 7, the scanning performance of the millimeter wave high isolation large scanning angle phased array antenna during large angle scanning. When the port phase difference is 150°, at the low frequency of 66GHz, the phased array antenna can scan up to 63 °, the grating lobe is low, and the gain drops by about 1.17dB; at the intermediate frequency 71GHz, the phased array antenna can scan to a maximum of 62°, with no obvious grating lobe, and the gain drops by about 1.07dB; at the high frequency 76GHz, the phased array antenna It can scan to a maximum of 64°, with no obvious grating lobes, and the gain drops by about 1.75dB.

As shown in Figure 8, the active return loss of the millimeter-wave high isolation large scanning angle phased array antenna when scanning at large angles, and the active S parameters of all ports when scanning to the maximum angle are lower than -10dB in the band.

The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, and combinations may be made without departing from the spirit and principles of the present invention. , simplification, should all be equivalent replacement methods, and are all included in the protection scope of the present invention.

Claims

An antenna unit, characterized in that it includes a first dielectric substrate, a first metal plate, a second dielectric substrate and a second metal plate arranged in close contact from top to bottom, and a radiating metal is arranged on the upper surface of the first dielectric substrate. patch, the first metal plate is connected to the second metal plate through metal pillars to form a dielectric cavity structure, and the coaxial line excites and radiates the metal patch through the feed point provided on the second metal plate.
The antenna unit according to claim 1, characterized in that the coaxial line passes through the feed point and excites the radiation metal patch through an L-shaped probe or a gap.
The antenna unit according to claim 2, wherein the L-shaped probe or slit is provided on the first metal plate and is on the same layer.
A sub-array composed of the antenna units according to any one of claims 1 to 3, characterized in that it includes 1×D antenna units and uses a one-D integrated waveguide feed network to excite the radiation metal patch.
The subarray according to claim 4, wherein the one-to-two D integrated waveguide feed network includes at least two one-to-two power dividers, each one-to-two power divider is arranged on the dielectric substrate and is located between two layers of metal plates.
The sub-array according to claim 4, wherein the metal plate is provided with a signal via hole, and the signal via hole includes a metal pillar and a circular metal patch.
The sub-array according to claim 4, wherein the one-D integrated waveguide feed network is surrounded by a circle of metal columns.
A millimeter-wave high-isolation large-angle phased array antenna composed of the sub-arrays according to any one of claims 4 to 7, characterized in that N×D antenna element arrays are composed of N sub-arrays, and an antenna with a vertical plane is provided The unit distance is 0.38λ. A decoupling structure is set between the two antenna units on the vertical plane of the antenna. It is on the same layer as the radiating metal patch and the spacing is 0.38λ. Metal patches are set on the upper and lower ends of the vertical plane of the antenna and are in contact with the radiating metal patch. The metal patches are on the same layer, and the spacing is 0.38λ, where λ is the free space wavelength of the antenna center frequency.
The millimeter-wave high-isolation large-angle phased array antenna according to claim 8, wherein the decoupling structure includes a U-shaped ground branch.
The millimeter-wave high-isolation large-angle phased array antenna according to claim 8, wherein the metal patch is a metasurface unit, a square patch, a rectangular patch, a parallelogram patch or a trapezoidal patch.