A dual-polarized microstrip patch antenna applied to a millimeter wave phased array

Abstract

The application discloses a dual-polarized microstrip patch antenna applied to a millimeter wave phased array, and belongs to the field of radio frequency front ends.The antenna mainly comprises two substrates and two patch structures, wherein the top patch is fed by two coaxial probes, the feeding port has two feeding slits, and the bottom patch is in a cross shape, which increases the cross-polarization ratio of the dual-polarized antenna radiation.The antenna realizes the dual-polarized characteristic at H plane + / -45 DEG, the 10dB relative bandwidth is 38.9%, and the radiation pattern half-power beam width is greater than 100 DEG. The antenna has the characteristics of simple structure and simple manufacturing, and can be rapidly printed and manufactured by adopting a planar microstrip structure.

Description

TECHNICAL FIELD

[0001] The application relates to a dual-polarized microstrip patch antenna mainly applied to a phased array antenna in a Ka frequency band and belongs to the field of radio frequency front-end devices. BACKGROUND

[0002] The dual-polarized antenna has important application value in the phased array antenna in the millimeter wave band due to multiple advantages such as frequency reuse, polarization diversity, strong anti-interference capability and anti-multipath fading. The dual-polarized antenna can adopt multiple antenna types, and the design method for realizing dual polarization can be mainly divided into two categories. The first category is to realize dual polarization by using the orthogonality of radiation units in spatial position or structure, and the second category is to realize dual polarization by exciting two different modes of the antenna itself to realize the orthogonality of electric fields. At present, the directivity and gain of the dual-polarized antenna at a lower frequency are relatively ideal, but after being applied to the millimeter wave band, the antennas designed by the two methods both have problems such as narrow bandwidth and non-ideal directivity, and are difficult to play a good role in the phased array.

[0003] Since the phased array antenna needs to be scanned at a large angle, a wide-band antenna with a wide directivity coverage angle is required. However, there is no such scheme in the prior art. SUMMARY

[0004] Therefore, the application provides a dual-polarized microstrip patch antenna applied to a phased array in a millimeter wave band. The antenna is based on the second method for realizing the dual-polarization characteristic of the antenna in the background technology, the designed antenna has a high bandwidth and can completely cover the working frequency band, and has a wide directivity and can better meet the scanning angle requirement of the phased array.

[0005] In order to achieve the above purpose, the technical scheme adopted by the application is as follows:

[0006] A dual-polarized microstrip patch antenna applied to a phased array in a millimeter wave band, comprising a first patch 1, a second patch 4, a first dielectric substrate 8, a second dielectric substrate 9, an adhesive layer 10, a metal ground 7 and a feed structure. The first dielectric substrate 8 is located on the top layer, the second dielectric substrate 9 is located on the bottom layer, and the adhesive layer 10 is used to connect the first dielectric substrate 8 and the second dielectric substrate 9. The first patch 1 is located above the first dielectric substrate 8, the second patch 4 is located above the second dielectric substrate 9, and the metal ground 7 is located below the second dielectric substrate 9. The feed structure comprises two coaxial probes 3, the coaxial probes 3 penetrate through the first dielectric substrate 8 and the second dielectric substrate 9, and the coaxial probes 3 have a gap 2 in the radial direction with the first patch 1 and the metal ground 7.

[0007] Further, the main body of the first patch 1 is formed by rotating a cross-shaped structure formed by cutting a rectangle structure from the four corners of a large square patch by 45 degrees, and there are a circular hollow area on each of the upper left branch and the upper right branch of the cross-shaped structure of the first patch 1, and there is a circular metal sheet in the center of each of the two circular hollow areas, and the radius of the circular metal sheet is equal to the radius of the coaxial probe 3, and the gap between the circular metal sheet and the cross-shaped structure of the first patch 1 is the slot 2.

[0008] Further, the radius of the coaxial probe 3 is greater than or equal to 150 microns, and the two coaxial probes 3 are located directly below the two circular metal sheets respectively, and each coaxial probe 3 is directly connected to the circular metal sheet above it to realize power feeding, and the axis of the slot 2 coincides with the axis of the coaxial probe 3.

[0009] Further, the distance from the coaxial probe 3 to the center of the first patch 1 is between 300 microns and 600 microns, and the width of the slot between the first patch 1 and the coaxial probe 3 is greater than or equal to 100 microns.

[0010] Further, the second patch 4 is a cross-shaped structure formed by cutting a rectangle structure from the four corners of a square structure, and the four cut rectangle structures are the same and symmetrically distributed about the center of the second patch 4; the minimum distance between the second patch 4 and the coaxial probe 3 is greater than or equal to 500 microns; and the horizontal length of the second patch 4 is greater than the vertical length.

[0011] Compared with the background art, the present application has the following advantages:

[0012] a) The bandwidth is wide, the 10dB bandwidth range is 26.3GHz-40GHz, close to 15GHz, and the antenna has good wideband characteristics in the coaxial line feeding antenna.

[0013] b) The antenna realizes dual polarization at H plane ±45°, and the corresponding radiation pattern half-power beam width is greater than 100°, wherein the H plane refers to the plane perpendicular to the patch 1, and the -45° direction refers to the direction clockwise around the center of the patch 1 by 45°.

[0014] c) The structure is simple and easy to manufacture, and does not need a complex feeding network, and the planar patch structure can realize rapid printing and manufacturing. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a top view of the first patch in an embodiment of the present application.

[0016] Figure 2 is a top view of the second patch in an embodiment of the present application.

[0017] Figure 3 is a side view of the overall structure of the antenna in an embodiment of the present application.

[0018] Figure 4 is an exploded view of the overall structure of the antenna in the embodiment of the present application.

[0019] Figure 5 is a reflection coefficient curve of the antenna in the embodiment of the present application.

[0020] Figure 6 is an H-plane (45°) radiation pattern of the antenna at 29 GHz in the embodiment of the present application. DETAILED DESCRIPTION

[0021] The specific embodiments of the present application will be further described in detail below with reference to the accompanying drawings and embodiments.

[0022] As shown in the drawings, Figures 1-4 a dual-polarized microstrip patch antenna applied to a millimeter wave phased array, which is a patch antenna based on two coaxial probe feedings, comprises a first patch 1, a second patch 4, a first dielectric substrate 8, a second dielectric substrate 9, a prepreg adhesive layer 10, a metal ground 7, and a feed structure; the first dielectric substrate 8 is located on the top layer, the second dielectric substrate 9 is located on the bottom layer, and the adhesive layer 10 is used to connect the first dielectric substrate 8 and the second dielectric substrate 9; the first patch 1 is located above the first dielectric substrate 8, the second patch 4 is located above the second dielectric substrate 9, and the metal ground 7 is located below the second dielectric substrate 9; the feed structure comprises two coaxial probes 3, the coaxial probes 3 penetrate through the first dielectric substrate 8 and the second dielectric substrate 9, and the coaxial probes 3 have a gap 2 in the radial direction with the first patch 1 and the metal ground 7; the main body of the first patch 1 is formed by cutting a cross-shaped structure formed by a large square patch at four corners of a rectangular structure and rotating it by 45°, the first patch 1 has a circular hollow area on each of the upper left and upper right branches of the cross-shaped structure, and each of the two circular hollow areas has a circular metal sheet in the center, the radius of the circular metal sheet is equal to that of the coaxial probe 3, and the gap between the circular metal sheet and the cross-shaped structure of the first patch 1 is the gap 2; the radius of the coaxial probe 3 is greater than or equal to 150 microns, the two coaxial probes 3 are located directly below the two circular metal sheets respectively, each coaxial probe 3 is directly connected to the circular metal sheet above it to realize feeding, and the axis of the gap 2 coincides with the axis of the coaxial probe 3; the second patch 4 is a cross-shaped structure formed by cutting a square structure at four corners of a rectangular structure, and the four cut rectangular structures are the same and symmetrically distributed about the center of the second patch 4; the minimum distance between the second patch 4 and the coaxial probe 3 is greater than or equal to 500 microns; the horizontal edge length of the second patch 4 is greater than the vertical edge length.

[0023] The unit input signal port structures of the antenna are the same and symmetrical in position, and are directly connected to the first patch 1.

[0024] Specifically,Figure 1 In the embodiment, the first patch 1 is a rotating cross-shaped structure, and the purpose of cutting the rectangular part is to adjust the working frequency band of the antenna and reduce the size of the upper patch; the positions of the two coaxial probes are left-right symmetrical about the center line of the substrate, are located at the intersection of the center point of the first patch 1 and the ±45° direction, and are between 300 microns and 600 microns away from the center, for adjusting impedance matching; the cut gap 2 can be used for capacitive compensation to perform impedance matching.

[0025] Figure 2 In the embodiment, the second patch 4 is a rectangular structure formed by cutting the four corners of a rectangular metal sheet, and the main function is to increase the isolation degree of the feed port, and adjusting the structure can increase the cross polarization of the antenna ±45° radiation pattern.

[0026] In order to reduce the loss, the metal material adopts a metal with small resistivity, such as aluminum, copper, gold, etc., and the dielectric substrates 8 and 9 adopt a material Taconic RF-30 with small loss.

[0027] The feed position of the coaxial probe 3 and the shape of the second patch 4 will have an important influence on the bandwidth, gain and port isolation of the antenna unit, which is specifically manifested as:

[0028] a) Since the central position of the coaxial probe affects the impedance matching of the antenna, too far or too close distance between the coaxial probe center and the patch 1 center, and too wide or too narrow gap ring will make the antenna bandwidth too small or even impedance mismatch;

[0029] b) Within a certain range, the larger the size of the small rectangular structure cut by the second patch 4, the higher the bandwidth of the overall antenna, the better the port isolation, and the larger the cross polarization.

[0030] Therefore, selecting a reasonable central position of the coaxial probe and the size structure of the second patch 4 is of great significance to improve the overall performance of the dual-polarized patch antenna.

[0031] In the following, the structure of the dual-polarized patch antenna is described in the form of a specific embodiment (the data unit is microns):

[0032] Figure 1 The size of the structure is:

[0033] Diameter D1=300, diameter D2=500, structure L1=720, structure L2=840;

[0034] Figure 2 The size of the structure is:

[0035] Structure L3=1400, structure L4=900, structure L5=500;

[0036] Figure 3 The size of the structure is:

[0037] The substrate width L6=3000, the medium substrate 8 thickness L7=254, the medium substrate 9 thickness L8=762, the adhesive layer 10 thickness L9=100, the patch and the metal layer thickness of the metal ground is 18, and the coaxial probe outer wall diameter L10=690.

[0038] At this time, the reflection coefficient simulation result diagram of the dual-polarized patch antenna unit is as shown in the figure:

[0039] Figure 4 The reflection coefficient curve of the dual-polarized patch antenna is shown in the figure, and it is shown that the S11 of the antenna unit in the frequency range of 26.35-40GHz is less than-10dB.

[0040] Figure 5 The H-plane radiation pattern of the dual-polarized patch antenna when the direction angle is 45° is shown in the figure, and the half-power beam width is greater than 100°.

[0041] In summary, the antenna of the application mainly consists of two patch structures, wherein the top patch is fed by two coaxial probes, the feed port has two feed slots, and the bottom patch is a cross type, which increases the cross-polarization ratio of the dual-polarized antenna radiation. The antenna of the application realizes the dual-polarized characteristics in the H-plane ±45°, the 10dB relative bandwidth is 38.9%, and the radiation pattern half-power beam width is greater than 100°. The antenna has the characteristics of simple structure and simple manufacturing, and adopts a planar microstrip structure, which can realize rapid printing manufacturing.

Claims

1. A dual-polarized microstrip patch antenna for millimeter-wave phased arrays, characterized in that, The device includes a first patch (1), a second patch (4), a first dielectric substrate (8), a second dielectric substrate (9), an adhesive layer (10), a metal ground (7), and a power supply structure. The first dielectric substrate (8) is located on the top layer, the second dielectric substrate (9) is located on the bottom layer, and the adhesive layer (10) is used to connect the first dielectric substrate (8) and the second dielectric substrate (9). The first patch (1) is located above the first dielectric substrate (8), the second patch (4) is located above the second dielectric substrate (9), and the metal ground (7) is located below the second dielectric substrate (9). The power supply structure includes two coaxial probes (3), which penetrate the first dielectric substrate (8) and the second dielectric substrate (9). The coaxial probes (3) have gaps (2) in the radial direction with both the first patch (1) and the metal ground (7). The main body of the first patch (1) is obtained by rotating the rectangular structure at the four corners of the large square patch into a cross shape by 45°. There is a circular hollow area on the upper left and upper right branches of the cross shape of the first patch (1). There is a circular metal piece in the center of each of the two circular hollow areas. The circular metal piece has the same radius as the coaxial probe (3). The gap between the circular metal piece and the cross shape of the first patch (1) is the gap (2). The radius of the coaxial probe (3) is greater than or equal to 150 micrometers. The two coaxial probes (3) are located directly below the two circular metal plates. Each coaxial probe (3) is directly connected to the circular metal plate above it to achieve power feeding. The axis of the gap (2) coincides with the axis of the coaxial probe (3).

2. The dual-polarized microstrip patch antenna for millimeter-wave phased arrays according to claim 1, characterized in that, The distance from the coaxial probe (3) to the center of the first patch (1) is between 300 micrometers and 600 micrometers, and the width of the gap between the first patch (1) and the coaxial probe (3) is greater than or equal to 100 micrometers.

3. A dual-polarized microstrip patch antenna for millimeter-wave phased arrays according to claim 2, characterized in that, The second patch (4) is a cross-shaped structure formed by cutting off the rectangular structures at the four corners of a square structure. The four cut rectangular structures are the same and are symmetrically distributed about the center of the second patch (4). The minimum distance between the second patch (4) and the coaxial probe (3) is greater than or equal to 500 micrometers. The horizontal side length of the second patch (4) is greater than the vertical side length.

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