Research On Circularly Polarized Microstrip Antenna Based On Satellite Communication

Satellite communication refers to the communication conducted by satellite as relay.Satellite communication has made great progress in the past half century.With the successful launch of Tiantong-01 satellite,China has also entered the mobile phone era of satellite mobile communication.For the handheld and miniaturized mobile terminal of Tiantong-01 satellite,its antenna should have the characteristics of broadband,circular polarization and wide beam.In this paper,four different types of antennas with different characteristics are designed for different application scenarios,and these four antennas can also communicate with the satellites in motion.The main work of this paper is as follows:1.A broadband circularly polarized microstrip antenna is designed,which is fed by slot coupling.The energy is coupled to the microstrip patch through a pair of orthogonal placed H-shaped slots and air layers through a halved Wilkinson power divider with 90 degree phase-shifting effect,thus achieving the effect of broadband circular polarization.This antenna is suitable for areas with low latitudes such as southern China.2.On the basis of the first antenna,a broadband circularly polarized microstrip antenna with folded conductive wall is designed.The radiation aperture of the antenna is constrained by loading folded conductive wall,and the main lobe width of the antenna is widened.The effect of loading folded conductive wall on the main lobe width of the antenna is analyzed in detail.This antenna is suitable for areas with high latitudes such as northern China.3.A broadband circularly polarized crossed dipole antenna with a back cavity is designed.Two cross-placed symmetric dipole antennas are fed by two coaxial lines through a halved Wilkinson power divider with 90 degree phase shifting.A metal back cavity is loaded around the antenna to optimize the antenna's axial ratio and other performances.This antenna is smaller than the previous two antennas and is suitable for the case of higher requirements for antenna size.4.Using the third broadband circularly polarized crossed dipole antenna as the unit antenna,a uniform planar antenna array is constructed.The appropriate unit spacing and feed phase difference are set to improve the antenna's gain to meet higher requirements.