Research On Wide Beam Circularly Polarized Antenna Unit And Array

The antenna of aircraft and andvanced radar is usually expected to have large scanning space and avoid interference, when it is searching object, so the antenna required better characteristics in its scanning angular and polarization. The phased array antenna can search and track target adaptively by controling phase of elements. It has high data transmission rate and fast scanning speed. The circular polarized wave can resist harmful environmental conditions. As a result, the wide-angle scanning phased array with circular polarization has great application value.The wide beam antenna is a good candidate for wide-angle scanning phased array. It is necessary to design wide beam circularly polarized antenna unit, before you want to get wide-angle scanning circularly polarized phased array. This paper is based on actual project, which describes project processing systematacially. It includes project specifications evaluation, unit design, array design, processing and test. The paper can provides a good reference for engineers. The designed antenna, which is safe, reliable and maintainable, satisfies the requirement of adaptable environment and standardization. So it has a great application value for engineering. The thesis structure is organized as follows:Chapter I The research background and significance are reviewed. Summarized the research background and recent developments about wide beam circularly polarized antenna unit and wide-angle scanning phased array. At last of the chapter, the structure arrangement of dissertation is given.Chapter II Briefly elaborated the theory of circularly polarized antenna and array, which includes the definition of circular polarization, three methods of circular polarization about microstrip, array scanning gain, scanning beam and array pattern calculation with mutual coupling. It provides the theory basis for design circularly polarized antenna array.Chapter III Firstly, the project specifications are given, and some important specifications are analyzed theoretically. Then based on the indicators, a three-dimensional ground antnna is desiged, which has good bandwidth and circularly polarized characteristics. But it is very difficult to process and realize double circular polarization simultaneously. Then a microstrip antenna is designed, which can satisfy the requirement of project and easily to process. So the microstrip antenna is chose as the last design. And one of the antenna elements is fabricated and tested.Chapter IV Firstly, some important array specifications are analyzed theoretically. And array which is made of the microstrip antenna unit is simulated. For engineering practicability, stability of antenna installation is designed. At last antenna array is fabricated and tested.Chapter V Concluded main contributions of the thesis and proposed possible improvement approaches.