Design of Dual Band and Dual Circular Polarization Feed Network

In this paper, a four-port feed network for K and Ka dual frequency and dual circular polarization is proposed. The feed network consists of a low frequency 3dB bridge, a high frequency 3dB bridge and two diplexers. The return loss of diplexer in band is better than 30dB, and the isolation is better than 100dB, which directly improves the performance of the whole network. The standing wave (VSWR) of the final feed network reaches 1.2 and the isolation reaches 110dB.