Study And Design Of Feed Based On Angular Diversity Antenna

Angular diversity antenna is a new type of anti-multipath interference scattering communication antenna.Since angular diversity antenna can achieve long-distance communication over the horizon, has anti-jamming features such as a narrow beam, narrow communicating channels, it is widely used in modern military communications. But with the development of scattering communication technology, miniaturization and high maneuverability of the antenna become important factors restricting the development of scattering communication.Because the angular diversity can not be achieved in small diameter parabolic using normal feed with large cross-section, the paper is on the study of feed with excellent performance of small diameter parabolic based on requirement.The main works are as follows:1. Study on the basic theory of angular diversity and parabolic antenna. First of all, the theory of angular diversity and geometric characteristics, radiation characteristics, defocusing characteristics of reflector antenna are analyzed. Finally,the dual beam angle relationships and feed’s space of angular diversity antenna are obtained. These results provide a theoretical basis for the selection of feed and design of small caliber angular diversity antenna.2. Design the feed. First of all, make contrast and analysis of corrugated horn and normal dielectric rod feed,then select suitable angular diversity antenna feed type. Then conduct the thorough research to the principle of dielectric rod feed,design three kinds of novel dielectric feed( three sections of taper dielectric rod feed, curve type of dielectric rod feed, dielectric tube feed). finally make contrast and analysis of three antennas,choose three sections of taper dielectric rod antenna as the angular diversity antenna feed. Experiment shows: compared with normal dielectric rod antenna, the three sections taper rod feed has a lower side lobes and rotational symmetry pattern characteristics.3. Design the small caliber angular diversity antenna. To verify the angular diversity can be achieved or not in the small diameter parabolic using three sections taper dielectric feed, we design a small-caliber angular diversity antenna. Firstly, analysis mutual coupling and radiation characteristics of two collocated dielectric rod feeds. Then test the two collocated rod feeds, and optimize the small-caliber angular diversity antenna according to the experimental results. Finally, test the antenna, result shows that dual beam angular meet requirements of angular diversity antenna and proves the rationality and applicability of three sections taper dielectric rod antenna.4. Study on reflectarray antenna with new feed applied in. Because of high cross section of parabolic, the reflector array antenna having equivalent parabolic characteristics is introduced. Analysis of the working principle of the reflector array antenna, element characteristics and radiation characteristics, we design a broadband reflector array antenna based on the three sections taper dielectric rod feed. Simulation results show that the direction of main beam norm to array surface, gain varies less than 0.5d B within 19% of the bandwidth, side lobe less than-20 d B.