A spaceborne low-intermodulation all-metal S-band circularly polarized array antenna

In response to the requirements of low profile, high reliability and low intermodulation multi-beam antennas for spaceborne multi-beam antennas, this paper designs an all-metal circularly polarized antenna array operating in the S-band. A cylindrical metal shielding cavity is added to the array unit. It supports and protects the patch antenna unit while increasing the isolation between units. The two-port feeding method enables the antenna to achieve good axial ratio characteristics and the feeding structure is simple. The paper uses a 2×2 scale rectangular grid arrangement for array verification. The simulation and test results show that the antenna unit and array have good circular polarization performance. Within the bandwidth of 1. 95GHz~2. 25GHz, the standing waves are all less than 2, the axial ratio is less than 1. 8dB, the impedance bandwidth and the relative bandwidth of the axial ratio are both greater than 14. 3%, and the circular polarization gain of the array meets ≥20dB. This antenna array is made of all-metal materials and has the advantages of simple structure, low profile, no complex feed network, low passive intermodulation, and low production cost, and has wide application value.