A broadband dual-polarized antenna operating in the X-band

Abstract

The invention discloses a broadband dual-polarized antenna working in the X-band, comprising a rectangular dielectric block, a dielectric plate, a feed microstrip line corroded on the front of the dielectric plate, a feed microstrip line corroded on the back of the dielectric plate, a resonant cavity and a dielectric sheet; the resonant cavity is a square cavity, the dielectric sheet covers the top cover of the resonant cavity, and the rectangular dielectric block is fixed on the upper surface of the dielectric sheet; a hole is opened on each of the adjacent two side walls of the resonant cavity, the dielectric plate is L-shaped and half-surrounded around the periphery of the resonant cavity, and a dielectric strip is extended from each of the two sides to the opposite side wall of the resonant cavity; the feed microstrip line corroded on the front of the dielectric plate and the feed microstrip line corroded on the back of the dielectric plate are respectively attached to the lower surface of a dielectric strip. The single dielectric plate dual-polarized feed balun structure of the invention is easy to realize antenna array; the antenna structure is compact, and the antenna is miniaturized.

Description

Technical Field

[0001] The invention belongs to the technical field of antennas, and in particular relates to a broadband dual-polarization antenna. Background Art

[0002] Dual-polarized antennas are widely used in wireless communications and radar systems due to their polarization diversity and ability to increase channel capacity. In the design and application of 2G / 3G / 4G / 5G base station antennas, for dual-polarized antennas operating below 6GHz, it is easy to achieve more than 45% broadband bandwidth and excellent radiation pattern, but the feed balun structure is relatively complex, and welding becomes difficult during the assembly of the feed balun, floor, and radiator, which is no longer applicable in practical applications; in the millimeter wave frequency band, the implementation of dual-polarized antennas often uses multi-layer printed circuit board (PCB) technology and low-temperature co-fired ceramic (LTCC) technology to achieve more than 40% broadband radiation. This is because of its shorter wavelength and the substrate height is sufficient to produce broadband bandwidth. For fire control radars, weather radars, and satellite communications, which are often used in the X-band for military and civilian applications, the longer wavelength limits the substrate height and cannot achieve ideal broadband radiation.

[0003] At present, domestic and foreign research on dual-polarized antennas in the X-band has been conducted. Xing Zhao, Bu Ning Tian and others have used multi-layer PCB technology to produce a dual-polarized antenna array, which retains the advantage of low profile, but its bandwidth is only 8.7%, and the operating frequency band can only cover 9.35-10.2GHz. The X-band dual-polarized antenna realized by the back cavity structure is also a common method. For example, the 2×2 substrate integrated cavity back dual-polarized array designed by Jing Wang, Wei Wang and others can achieve a bandwidth of 29.89%; the substrate integrated back cavity dual-polarized antenna designed by Rajesh C. Paryani can only achieve a bandwidth of 19%; the dual-polarized differential slot antenna designed by Gunjan Srivastava and Akhilesh Mohan only achieves a bandwidth of 2.2%.

[0004] Whether the existing technology adopts a multi-layer PCB process or a back cavity structure, it is difficult to achieve a bandwidth of more than 40%, that is, it is difficult to achieve full coverage of the X-band. Summary of the invention

[0005] In order to overcome the shortcomings of the prior art, the present invention provides a broadband dual-polarized antenna working in the X-band, comprising a rectangular dielectric block, a dielectric plate, a feed microstrip line corroded on the front of the dielectric plate, a feed microstrip line corroded on the back of the dielectric plate, a resonant cavity and a dielectric sheet; the resonant cavity is a square cavity, the dielectric sheet covers the top cover of the resonant cavity, and the rectangular dielectric block is fixed on the upper surface of the dielectric sheet; a hole is opened on each of the adjacent two side walls of the resonant cavity, the dielectric plate is L-shaped and half-surrounded by the periphery of the resonant cavity, and a dielectric strip is extended from each of the two sides to the opposite side wall of the resonant cavity; the feed microstrip line corroded on the front of the dielectric plate and the feed microstrip line corroded on the back of the dielectric plate are respectively attached to the lower surface of a dielectric strip. The single dielectric plate dual-polarized feed balun structure of the present invention is easy to realize antenna array; the antenna structure is compact, and the antenna is miniaturized.

[0006] The technical solution adopted by the present invention to solve the technical problem includes the following steps:

[0007] A broadband dual-polarized antenna operating in the X-band, comprising a rectangular parallelepiped dielectric block, a dielectric plate, a feed microstrip line corroded on the front side of the dielectric plate, a feed microstrip line corroded on the back side of the dielectric plate, a resonant cavity and a dielectric plate, a first metal patch and a second metal patch;

[0008] The resonant cavity is a square cavity, the top cover of the resonant cavity is provided with a circular hole tangent to the four side walls of the resonant cavity, and tooth-like structures extend from the four side walls into the circular hole, and the tooth-like structures increase the current path; the dielectric sheet covers the top cover of the resonant cavity; the rectangular parallelepiped dielectric block is fixed on the upper surface of the dielectric sheet;

[0009] The adjacent two side walls of the resonant cavity each have a hole, which are a first hole and a second hole respectively;

[0010] The dielectric plate is L-shaped and half surrounds the periphery of the resonant cavity. A dielectric strip extends from each of the two sides of the dielectric plate and passes through the first hole and the second hole respectively into the resonant cavity to the opposite side wall of the resonant cavity. The two dielectric strips form an orthogonal structure.

[0011] The first metal patch is attached to the upper surface of the dielectric plate; the second metal patch is attached to the lower surface of the dielectric plate;

[0012] The feeding microstrip line corroded on the front side of the dielectric plate is attached to the upper surface of a dielectric strip, and the feeding microstrip line corroded on the back side of the dielectric plate is attached to the lower surface of another dielectric strip; a first notch is made on the feeding microstrip line corroded on the front side of the dielectric plate at the orthogonal intersection of the two dielectric strips, and a second notch is made on the feeding microstrip line corroded on the back side of the dielectric plate to reduce the cross-polarization level and improve the port isolation; the feeding microstrip line corroded on the front side of the dielectric plate extends to the L-shaped portion of the dielectric plate to form a first 50-ohm matching section, and the end of the first 50-ohm matching section is connected to the second metal patch; the feeding microstrip line corroded on the back side of the dielectric plate extends to the L-shaped portion of the dielectric plate to form a second 50-ohm matching section, and the end of the second 50-ohm matching section is connected to the second metal patch.

[0013] Preferably, the dielectric plate and the dielectric sheet are made of Rogers RO4350 dielectric plate, and the relative dielectric constant is 3.66.

[0014] Preferably, the rectangular parallelepiped dielectric block is made of a material with a relative dielectric constant of 5.9.

[0015] The beneficial effects of the present invention are as follows:

[0016] 1. The dielectric loading of the present invention is applied to the X-band to achieve bandwidth broadening and impedance matching;

[0017] 2. The present invention adjusts the feed balun gap to reduce the cross-polarization level and port isolation;

[0018] 3. The single dielectric plate dual-polarization feeding balun structure of the present invention can easily realize antenna array;

[0019] 4. The antenna structure of the present invention is compact, and the antenna is miniaturized. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a side view of the antenna of the present invention.

[0021] Figure 2 This is a front view of the antenna of the present invention.

[0022] Figure 3 This is a top view of the antenna of the present invention after removing the rectangular parallelepiped dielectric block and the dielectric sheet.

[0023] Figure 4 It is a top view of the resonant cavity of the present invention.

[0024] Figure 5 It is a front view of the resonant cavity of the present invention.

[0025] Figure 6 It is the S parameter diagram of the antenna of the present invention.

[0026] Figure 7This is the radiation pattern at 8 GHz frequency.

[0027] Figure 8 This is the radiation pattern at 10 GHz frequency.

[0028] Fig. 9 This is the radiation pattern at 12GHz frequency.

[0029] Figure numerals: 1-rectangular dielectric block, 2-dielectric plate, 3-feeding microstrip line corroded on the front side of the dielectric plate, 4-feeding microstrip line corroded on the back side of the dielectric plate, 5-resonant cavity, 6-dielectric plate, 7-first metal patch, 8-second metal patch, 501 first hole, 502 second hole, 301 first notch, 401 second notch, 302 first 50 ohm matching section, 402 second 50 ohm matching section. DETAILED DESCRIPTION

[0030] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0031] The purpose of the present invention is to overcome the shortcomings of the prior art and, by using a dielectric loading method, provide a broadband cavity-backed dual-polarized antenna suitable for full coverage of the X-band (8-12GHz), which is easy to integrate, compact in structure, has a wide operating bandwidth, a low cross-polarization level, and high port isolation.

[0032] like Figure 1 and Figure 2 As shown, a broadband dual-polarized antenna working in the X-band includes a rectangular dielectric block 1, a dielectric plate 2, a feeding microstrip line 3 corroded on the front side of the dielectric plate, a feeding microstrip line 4 corroded on the back side of the dielectric plate, a resonant cavity 5 and a dielectric plate 6, a first metal patch 7 and a second metal patch 8;

[0033] like Figure 4 and Figure 5 As shown, the resonant cavity 5 is a square cavity, the top cover of the resonant cavity 5 is provided with a circular hole tangent to the four side walls of the resonant cavity 5, and tooth-like structures extend from the four side walls into the circular hole, and the tooth-like structures increase the current path; the dielectric sheet 6 covers the top cover of the resonant cavity 5; the rectangular parallelepiped dielectric block 1 is fixed on the upper surface of the dielectric sheet 6;

[0034] The adjacent two side walls of the resonant cavity 5 each have a hole, which are a first hole 501 and a second hole 502;

[0035] like Figure 3 As shown, the dielectric plate 2 is L-shaped and half surrounds the periphery of the resonant cavity 5. A dielectric strip extends from each of the two sides of the dielectric plate 2 and passes through the first hole 501 and the second hole 502 respectively to enter the resonant cavity 5 and reach the opposite side wall of the resonant cavity 5. The two dielectric strips form an orthogonal structure.

[0036] The first metal patch 7 is attached to the upper surface of the dielectric plate 2; the second metal patch 8 is attached to the lower surface of the dielectric plate 2;

[0037] The feeding microstrip line 3 corroded on the front side of the dielectric plate is attached to the upper surface of a dielectric strip, and the feeding microstrip line 4 corroded on the back side of the dielectric plate is attached to the lower surface of another dielectric strip; a first notch 301 is made on the feeding microstrip line 3 corroded on the front side of the dielectric plate at the orthogonal intersection of the two dielectric strips, and a second notch 401 is made on the feeding microstrip line 4 corroded on the back side of the dielectric plate to reduce the cross-polarization level and improve the port isolation; the feeding microstrip line 3 corroded on the front side of the dielectric plate extends to the L-shaped portion of the dielectric plate 2 to form a first 50-ohm matching section 302, and the end of the first 50-ohm matching section 302 is connected to the second metal patch 8; the feeding microstrip line 4 corroded on the back side of the dielectric plate extends to the L-shaped portion of the dielectric plate 2 to form a second 50-ohm matching section 402, and the end of the second 50-ohm matching section 402 is connected to the second metal patch 7. Specific embodiment:

[0039] Using HFSS simulation software to design Figure 1 The antenna model is simulated and the simulation results are as follows Figure 6-Figure 9 shown.

[0040] The S parameters of the antenna are as follows: Figure 6 As shown, the return loss |S 11 |with|S 22 |In the entire X-band, it is less than -10dB, and the port isolation |S 21 |Higher than 20dB in X-band, achieving more than 40% impedance bandwidth, meeting full coverage of X-band.

[0041] The radiation pattern of the antenna is as follows Figures 7 to 9 As shown in the figure, from the radiation patterns at the three frequency points of 8 GHz, 10 GHz and 12 GHz, it can be seen that it has good end-fire radiation characteristics, and its cross-polarization level is less than -17 dB.

[0042] In general, the antenna of the present invention has:

[0043] 1. The structure of the feed balun is simple. The dual-polarization feed structure can be realized using only one dielectric plate. The gap in the middle of the feed balun can improve the port isolation and reduce the cross-polarization level.

[0044] 2. Easy to integrate. The feeding balun has a simple structure and is easy to connect to the RF circuit and form an array.

[0045] 3. The circular slot structure with teeth increases the current path to reduce the slot size.

[0046] 4. The medium loading technology is adopted, and the shapes of medium loading are various, including cuboid and cylinder.

Claims

1. A broadband dual-polarized antenna operating in the X-band, characterized in that: It includes a rectangular parallelepiped dielectric block, a dielectric plate, a feed microstrip line corroded on the front side of the dielectric plate, a feed microstrip line corroded on the back side of the dielectric plate, a resonant cavity and a dielectric plate, a first metal patch and a second metal patch; The resonant cavity is a square cavity, the top cover of the resonant cavity is provided with a circular hole tangent to the four side walls of the resonant cavity, and tooth-like structures extend from the four side walls into the circular hole, and the tooth-like structures increase the current path; the dielectric sheet covers the top cover of the resonant cavity; the rectangular parallelepiped dielectric block is fixed on the upper surface of the dielectric sheet; The adjacent two side walls of the resonant cavity each have a hole, which are a first hole and a second hole respectively; The dielectric plate is L-shaped and half surrounds the periphery of the resonant cavity. A dielectric strip extends from each of the two sides of the dielectric plate and passes through the first hole and the second hole respectively into the resonant cavity to the opposite side wall of the resonant cavity. The two dielectric strips form an orthogonal structure. The first metal patch is attached to the upper surface of the dielectric plate; the second metal patch is attached to the lower surface of the dielectric plate; The feeding microstrip line corroded on the front side of the dielectric plate is attached to the upper surface of a dielectric strip, and the feeding microstrip line corroded on the back side of the dielectric plate is attached to the lower surface of another dielectric strip; a first notch is made on the feeding microstrip line corroded on the front side of the dielectric plate at the orthogonal intersection of the two dielectric strips, and a second notch is made on the feeding microstrip line corroded on the back side of the dielectric plate to reduce the cross-polarization level and improve the port isolation; the feeding microstrip line corroded on the front side of the dielectric plate extends to the L-shaped portion of the dielectric plate to form a first 50-ohm matching section, and the end of the first 50-ohm matching section is connected to the second metal patch; the feeding microstrip line corroded on the back side of the dielectric plate extends to the L-shaped portion of the dielectric plate to form a second 50-ohm matching section, and the end of the second 50-ohm matching section is connected to the second metal patch.

2. A broadband dual-polarized antenna operating in the X-band according to claim 1, characterized in that: The dielectric plate and the dielectric sheet are made of Rogers RO4350 dielectric plate, and the relative dielectric constant is 3.

66.

3. The broadband dual-polarized antenna operating in the X-band according to claim 1, characterized in that: The rectangular parallelepiped dielectric block is made of a material with a relative dielectric constant of 5.9.

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