Research And Design Of Circularly Polarized Waveguide Slot Antenna

Waveguide slot array antennas consist of a variety of slots which line up according to certain rules on the waveguide wall. It has the advantages of high gain, high efficiency, low sidelobe, etc. But the circularly polarized waveguide slot antennas integrate the advantages of the waveguide slot antennas and the circularly polarized antennas. So they are widely used in radar, satellite communications and electronic countermeasures.This paper focuses on researching and designing of circularly polarized Ka-band waveguide slot array antennas. And the parameter extraction method which is suitable for the multi-slot structure is derived by combineing with Taylor synthesis method. At first, the research background and significance of circularly polarized waveguide slot antenna are introduced, and its development history and research status are shown briefly. Secondly, the transmission characteristics of rectangular waveguide, the radiation theory of waveguide slot and the relevant parameters of antenna are described. And the difference between Gain and Realized Gain in the High Frequency Simulation Software are compared and analyzed. Then, the related design methods of array antenna are discussed, which include early antenna design method, pattern synthesis method and nowadays design method with the commercial software. And a brief introduction of designing method of the standing wave array antennas and the traveling wave array antenna are given. Thirdly, according to the antenna’s design specifications, the researching and designing of circularly polarized Ka-band waveguide slot array antennas are given in detail. In order to make the array antennas composed with good axial ratio performance and wide operating band, not only need the structure is relatively simple and good performance on circular polarization, but also need arrange each slot unit in accordance with the amplitude of the Taylor distribution. But the unit structure of the circularly polarized waveguide slot antennas is a multi-slot structure, Taylor distribution can not be used in it directly. So, the parameter extraction method which is suitable for the multi-slot structure is derived by combineing with Taylor synthesis method. Finally, the circularly polarized Ka-band waveguide slot linear array antennas are designed, which are meeting the technical indicators. And the plane array antennas are formed. And the simulation results are analyzed. In order to achieve terminal matching of a linear array, the match slots are designed. At last, the linear array antennas are manufactured and tested. And the test results and the simulation results are basically the same.