CN-116315625-B - Circular polarization scanning grid array based on broadband 90-degree balun

Abstract

The invention discloses a circularly polarized scanning grid array based on a broadband 90-degree balun, and belongs to the technical field of microwave antennas. The array is formed by arranging circularly polarized antenna units in a grid mode, and the circularly polarized antenna units comprise a radiation patch layer, a first dielectric substrate, an air gap layer, a metal grounding layer, a second dielectric substrate and a feed network layer which are sequentially arranged from top to bottom. The circularly polarized antenna unit takes the rotationally placed microstrip patch as a radiator, adopts a metal back cavity to realize stable unidirectional radiation, can effectively reduce the coupling between the units after antenna array, and adopts a 180-degree power division phase shift network to combine an ultra-wideband phase shifter for a lower layer feed network, so that the broadband phase shift can be realized to a great extent, and the impedance bandwidth and the axial ratio bandwidth of the circularly polarized antenna are widened.

Inventors

• DING XIAO
• LIU XIANGYU

Assignees

• 电子科技大学

Dates

Publication Date

20260505

Application Date

20230104

Claims (4)

1. 1. A circularly polarized scanning grid array based on broadband 90-degree balun is characterized in that the array consists of a circularly polarized antenna unit grid array; the circularly polarized antenna unit comprises a radiation patch layer, a first dielectric substrate, an air gap layer, a metal grounding layer, a second dielectric substrate and a feed network layer which are sequentially arranged from top to bottom; The radiation patch layer comprises four radiation patches which are arranged on the upper surface of the first dielectric substrate and are rotationally symmetrical at 90 degrees, wherein a feed point is arranged on the radiation patches, and an annular coupling slot is arranged at the outer side of the feed point; the feed network layer is of a central symmetrical structure and is used for feeding signals with equal amplitude and phase difference of 90 degrees to 4 radiation patches in sequence, and comprises a 180-degree power division phase shifter, two T-shaped junction power splitters, two broadband 90-degree balun and two bending microstrip lines; the center of the 180-degree power division phase shifter coincides with the center of the circularly polarized antenna unit, and the 180-degree power division phase shifter comprises a feed gap and two sections of gradual change microstrip lines symmetrically arranged at two sides of the feed gap, wherein two output ends of the 180-degree power division phase shifter are respectively connected with a T-shaped junction power divider; One output end of the T-shaped junction power divider is connected with the input end of the bending microstrip line, and the other output end of the T-shaped junction power divider is connected with the broadband 90-degree balun; The broadband 90-degree balun is formed by arranging a first coupling line and a second coupling line which are in parallel and have the electrical length of 90 degrees, wherein one end of the first coupling line and one end of the second coupling line are connected with a short circuit point through a first microstrip line, the other end of the first coupling line is connected with the output end of a T-shaped junction power divider, and the other end of the second coupling line is connected with a feed point of a radiation patch through a feed copper column; the short circuit point is connected with the metal grounding layer through a metal through hole; The output end of the bending microstrip line is connected with a feed point of the radiation patch through a feed copper column; The radiating patch is a rectangular metal patch with the length-width ratio of 2.3-2.6, and the feed point is positioned at the center of the short side of the rectangular patch adjacent to the edge of the circularly polarized antenna unit.
2. 2. The array of claim 1, wherein the first dielectric substrate is of the type R5880, the dielectric constant is 2.2, the thickness of the dielectric plate is 5.2mm, the second dielectric substrate is of the type RO4350B, the dielectric constant is 3.48, and the thickness of the dielectric substrate is 0.508mm.
3. 3. A broadband 90 ° balun-based circular polarization scan grid array according to claim 1, wherein each bend of said bent microstrip line is a 90 ° bend, and an outside corner cut process at the 90 ° bend reduces the discontinuity of the microstrip transmission line at the bend.
4. 4. A broadband 90 ° balun-based circular polarization scanning grid array according to claim 3, wherein a ring of metal fence is provided on the outside of said circular polarization antenna unit.

Description

Circular polarization scanning grid array based on broadband 90-degree balun Technical Field The invention belongs to the technical field of microwave antennas, and particularly relates to a circularly polarized scanning grid array based on a broadband 90-degree balun. Background Broadband phased arrays have important applications in many areas. The rapid progress of modern communication technology makes the frequency hopping range wider and the frequency hopping rate higher, and if the performance of the antenna has a very narrow working bandwidth, it cannot meet the requirements of various users on modern communication. In the field of radars, the broadband phased array technology is an important approach for solving the problems of multi-target resolution, target identification, attribute judgment and the like, has great significance on the field of military, improves the channel capacity of communication and avoids channel congestion due to the increase of the phased array bandwidth in the field of communication, and allows the phased array to have the functions of detection, electronic countermeasure, communication and the like in a wider bandwidth in the multifunctional application, so that the multifunctional integrated phased array is possible. Antennas can be classified into linear polarization, circular polarization, and elliptical polarization according to the variation of the electric field direction. Compared with a linear polarization antenna, the circular polarization antenna has many advantages that when a linear polarization wave passes through a rain and fog area, polarization deflection is easy to occur to cause energy loss, and the circular polarization wave passes through the rain and fog area and is blocked from reversing the rotation direction of a reflected wave, is isolated from the polarization of an incident wave, has strong anti-interference and anti-attenuation capabilities, and can be received by a horizontal polarization antenna and a vertical polarization antenna at the same time. Therefore, the circularly polarized phased array antenna has better anti-interference and anti-rain and fog attenuation capability, and is widely applied to satellite communication. Therefore, the broadband circularly polarized phased array antenna is researched, so that the array antenna formed by the broadband circularly polarized phased array antenna can realize circular polarization large-angle scanning, and the broadband circularly polarized phased array antenna has great research significance and engineering significance. Patent document 201910692191.5 discloses a broadband circular polarization array antenna, wherein a central feed network comprises a square patch with an opening, four corners of the square patch are connected with a branch-shaped patch, the branch-shaped patches are arranged in a structure rotated by 90 degrees, and the advantages of wide impedance matching bandwidth, wide axial ratio bandwidth and good circular polarization characteristic are realized. But the antenna is large in size and inconvenient to form an array antenna, and does not consider the coupling between antenna elements, and does not have the potential to form an antenna array. CN114665254a (patent document with application number 202111446979.1 discloses a wideband circularly polarized array antenna with sequential phase feeding and a wearable device thereof, wherein one side of a dielectric substrate is a radiating unit, and the other side is a coupling slot unit. At present, the research on ultra-wideband circular polarization scanning arrays is relatively few, and the intensive research on how to realize the wide-angle scanning of ultra-wideband circular polarization is also needed. Disclosure of Invention The invention aims to overcome the defects of the prior art and provide a circularly polarized scanning grid array based on a broadband 90-degree balun. The antenna array comprises a circular polarization antenna unit grid array, wherein the circular polarization antenna unit is divided into a radiator, a metal back cavity and an ultra-wideband feed network, a microstrip patch which is arranged in a rotating mode is used as the radiator, the metal back cavity is used for realizing stable unidirectional radiation, the structure can effectively reduce coupling among the units after the antenna array is assembled, and the lower-layer feed network adopts a 180-degree power division phase shift network to combine the ultra-wideband phase shifter, so that the impedance bandwidth and the axial ratio bandwidth of the antenna can be greatly improved. The technical scheme adopted by the invention is as follows: a circularly polarized scanning grid array based on broadband 90-degree balun is characterized by comprising a circularly polarized antenna unit grid array. The circularly polarized antenna unit comprises a radiation patch layer, a first dielectric substrate, an air gap layer, a metal grounding layer, a s