Research On Phased Array Antenna For Maritime Satellite Communication System Terminal

Traditional maritime satellite communication terminal antenna is composed of complex servo stable tracking system and antenna radiation unit, which is expensive and depends on imports. Phased array antenna has the advantages of low cost and fast phase change, which can quickly point to the satellite, so it is significant to study the phased array antenna of the maritime satellite communication terminal.In support of the project of Liaoning Province Education Department "Research on the phased array antenna of broadband global area network mobile communication terminal", this paper conducts the research and design of phased array antenna. Details are as follows:(1) Artificial bee colony algorithm is used to optimize the excitation amplitude and phase of the phased array antenna, the low sidelobe and nulls are achieved respectively. With the optimization of array excitation amplitude distribution, the sidelobe level of antenna pattern in beam scanning is reduced. When the scanning angle θ=-40°, the sidelobe level is reduced by -9dB.(2) A 360 degree analog phase shifter based on left hand transmission line is designed. In the voltage range of 0-6V, the phase shift reaches 360 degree. The insertion loss is less than 3dB and the the linearity is less than 4.1%, and the whole size of the phase shifter is 15mm×25mm.(3) A cross slot coupled feed circular polarized antenna array is designed and implemented. The parasitic patch is attached to the radiation patch to improve the axial ratio bandwidth of antenna array, while the reflector plate is added to reduce the backward radiation of the antenna. The relative impedance bandwidth of the antenna array reachs 24.3%. A four ways unequal power divider network based on recombinant technology is designed, whose power ratio meets the -30dB Chebyshev amplitude distribution 1:5.4:5.4:1. The reflection coefficient of each port is less than -15dB, the isolation is greater than 18dB, and the output phase difference is less than 2 degrees.(4) The coaxial cable is used to connect the power divider network, analog phase shifter and antenna array to achieve the phased array antenna. The actual test results show that in the frequency range of 1.41-1.72GHz, the antenna input voltage standing wave ratio was less than 2.0, and the phased array antenna realize ±20 degree beam scanning angle.