CN-116505258-B - Low-axial-ratio circularly polarized antenna with isolation structure

CN116505258BCN 116505258 BCN116505258 BCN 116505258BCN-116505258-B

Abstract

The invention discloses a low-axial-ratio high-power-capacity circularly polarized antenna with an isolation structure, and belongs to the technical field of high-power microwave measurement. According to the invention, an isolation structure is added between the circular polarization generating structure and the feed structure of the antenna to inhibit the influence of different connection structures at the rear end of the antenna. The typical isolation structure is a metal surface which expands backwards, on one hand, the forward reflection of the isolation structure is well restrained through proper inclination design, the influence on the front-end circular polarization generating structure is reduced, the low axial ratio characteristic is guaranteed, on the other hand, due to proper depth and size design, the backward transmission of surface current and the reflection of the rear-end metal surface are effectively restrained, the influence of the rear-end connecting structure on the low axial ratio characteristic of the antenna is reduced, and finally, the circular polarization antenna with the ultralow axial ratio is obtained through actual measurement verification. The isolation structure provided by the invention effectively inhibits the backward transmission of surface current and the reflection inhibition of the rear metal surface on the basis of not affecting the low axial ratio characteristic of the antenna.

Inventors

LIU XIUHAN
YANG MENG
HAO WENXI
YAN FENG
LIU MIN

Assignees

中国人民解放军63660部队

Dates

Publication Date: 20260505
Application Date: 20221208

Claims (3)

1. The low-axial-ratio circularly polarized antenna with the isolation structure comprises a circularly polarized feed structure, a circularly polarized generating structure and a mounting flange, and is characterized by further comprising the isolation structure; the isolating structure is a metal emitting surface which expands backwards and is positioned behind the circular polarization generating structure The position is nested on the circularly polarized feed structure, and the inclination angle of the isolation structure is adjusted And the size of the emitting surface of the isolation structure 、 ) Is used for ensuring the low axial ratio characteristic of the antenna and simultaneously effectively inhibiting the backward transmission of surface current and the reflection of a rear metal surface, wherein For isolating the emitting surface of the structure from the inclination angle formed by the circular polarization generating structure, For the length of the emitting surface, Is the width of the emitting surface; the distance between the isolation structure and the circular polarization generating structure is The isolation structure can slide back and forth on the circular polarization generating structure to realize the frequency modulation function of the circular polarization antenna, and the size of the emitting surface of the isolation structure is # 、 ) Under the condition that the size of the rear-end metal reflecting surface is larger than or approximately equal to that of the rear-end metal reflecting surface, the reflection inhibition effect is better, and the size design is adapted according to the application scene By the length of the insulating structural section And the size of the emitting surface 、 ) Co-determination, keeping the emitting surface size% 、 ) Under the condition of no change, the larger the inclination angle of the isolation structure is, the narrower the axial ratio beam width of the circularly polarized antenna is, and the inclination angle of the isolation structure is smaller than the value under the condition of adapting to an application scene; The rear end of the circular polarization feed structure is connected with a standard flange for mounting and fixing an antenna, the front end of the circular polarization feed structure is connected with a circular polarization generating structure to generate circular polarized waves, and the circular polarization generating structure and the isolation structure are integrated to realize technical indexes of low axial ratio, wide wave beam and high power capacity.
2. The low axial ratio circularly polarized antenna with isolation structures of claim 1, wherein the isolation structures are prismatic, circular truncated cone, or other suitable application scenario types.
3. The low axial ratio circularly polarized antenna with the isolation structure according to claim 1 is characterized in that in an X frequency band, the isolation structure is a prismatic table type metal emitting surface which expands backwards, the circularly polarized feed structure is a rectangular waveguide transmission section and adopts BJ100 type waveguides, the circularly polarized generation structure is a waveguide slotting section, the waveguide slotting section comprises a first special-shaped slot and a second special-shaped slot, and the two special-shaped slots are rotationally symmetrical structures.

Description

Low-axial-ratio circularly polarized antenna with isolation structure Technical Field The invention belongs to the technical field of high-power microwave measurement, and particularly relates to a low-axial-ratio circularly polarized antenna with an isolation structure. Background Antennas are a key component of wireless communication systems and play an important role at both signal transmitting and receiving ends. For the linear polarization antenna, the requirements on the polarization matching condition of the receiving and transmitting system are strict, when the polarization direction of the receiving and transmitting system has an included angle, a certain loss is generated on the received signal, and when the polarization direction of the receiving and transmitting system is vertical, the receiving and transmitting ends are completely isolated. According to the polarization theory, any linear polarized wave can be decomposed into two circular polarized waves with opposite rotation directions and equal amplitude, so that the circular polarized antenna can effectively receive any linear polarized wave, has obvious advantages in solving the problem of polarization mismatch, and particularly when the axial ratio of the circular polarized antenna is low enough, the received signal strength is always unchanged no matter how the direction of the linear polarized incoming wave changes. The ideal circular polarized antenna has constant polarization loss coefficient for linearly polarized waves in any direction, and can realize the reception of the linearly polarized waves in any direction so as to avoid the problem of polarization mismatch. The practical circular polarized antenna is affected by factors such as processing errors, use environments and the like, and is usually represented as elliptical polarization characteristics with a certain axial ratio, and when the antenna is used for accurately measuring high-power microwave signals with unknown polarization directions, how to improve the axial ratio characteristics of the circular polarized antenna, inhibit the influence of the use environments, and meet the requirement of high-power capacity at the same time is a problem that the design of the circular polarized antenna needs to be considered seriously. At present, many researches on low-axial-ratio circularly polarized antennas have been carried out at home and abroad, and a circularly polarized antenna designed based on a circularly polarized converter, a corrugated horn, a waveguide slot structure and the like is typical. However, the circularly polarized antenna provided in the related literature or example is usually an elliptical polarized antenna with an axial ratio of 0.5dB-3dB, and the axial ratio measured result is usually higher than the simulation result by more than 1dB, and the analysis is mainly because a designer only pays attention to the performance of the antenna, and the influence of a rear end connection structure and a use test environment on the axial ratio characteristic of the antenna in the actual use process is ignored. Therefore, a practical and effective low-axial-ratio circularly polarized antenna design scheme is still lacking to meet the high-precision measurement requirement of high-power microwave signals with unknown polarization directions. Disclosure of Invention The invention aims to provide a low-axial-ratio circularly polarized antenna with an isolation structure, which is used for effectively inhibiting backward transmission of surface current and reflection of a rear metal surface through the isolation structure, solving the problems that the current practical circularly polarized antenna is affected by factors such as processing errors, use environments and the like, has poor axial ratio characteristics, poor scattering inhibition and the like, has the characteristic of high power capacity and is suitable for the requirement of accurately measuring high-power microwave signals with unknown polarization directions in different application scenes. In order to achieve the above purpose, the technical scheme of the invention is as follows: a low axial ratio circularly polarized antenna with an isolation structure comprises a circularly polarized feed structure, a circularly polarized generating structure, a mounting flange and an isolation structure; The isolation structure is a metal emission surface which expands backwards and is positioned at the position l 2 behind the circular polarization generating structure and is nested on the circular polarization feed structure, and the inclination angle theta of the isolation structure and the size (a 1、b1) of the emission surface of the isolation structure are adjusted, wherein theta is the inclination angle formed by the emission surface of the isolation structure and the circular polarization generating structure, a 1 is the length of the emission surface, b 1 is the width of the emission surface; The distance bet