Compact Dual Band Dual Circularly Polarized User-cum-Gateway Feed Chain for Multiple Beam Antennas at K/Ka Bands

摘要

This paper describes the design of a compact dual band dual circularly polarized feed chain for satellite communication antennas at K/Ka bands. The proposed feed chain caters to User-cum-Hub bands (Transmit: 17.720.7GHz & Receive: 27.5-30.5GHz) with a transverse envelope of 40mm*20mm which is suitable for multiple beam antennas having small feed-feed spacing due to smaller beam size. The chain consists of a dual band septum polarizer with high bandwidth of individual bands and transmit/receive diplexer for frequency separation. The comparative R.F performance of two configurations based on circular and square septum polariser is elucidated. The analysis of the feed chain components was carried out using two different techniques namely 2D-FEM/MM and FEM through commercially available softwares Mician and HFSS respectively and there is a close match in the results. The high performance circularly polarized feed chain was optimized in an integrated manner for Axial ratio <1 dB.