Research Of Broadband And Dual Circularly Polarized Microstrip Phased Array Antenna Element

Becouse of the fast beam scanning capacity and the characteristics of rapid change in beam shape, phased array antenna has become the mainstream of development. Based on the array antenna theory, the scanning principles of phased array antenna was introduced.,then the requirements of the phased array antenna elements,such as beam width and elements'spacing,were analysed.The phased array antenna designed in this paper is applied to the high altitude platform station(HAPS).Microstrip antennas are particularly suitable for HAPS system due to their inherent advantages like light weight, low profile,easy conformity with carrier and so on. Circularly polarized antenna can accept incoming wave of any polarization and the circularly polarized electromagnetic waves can be accepted by any polarized antenna.Those characteristics make circularly polarized antenna increasingly popular.The thesis summarizes the broadening method of microstrip antenna' impedance bandwidth and axial ratio bandwidth,and then designs a broadband,dual circularly polarized microstrip phased array antenna element which used in the HAPS system. By Using the C-gap in the microstrip patch and multilayer structure,the antenna element' impedance bandwidth and axial ratio bandwidth were broadened to 16% and 18%,meeting the system'requirement.At last,the rectangular plane array antenna which formed by this element was researched,and the array antenna'side lobe was optimizated.