Simulation of A 90o Differential Phase Shifter for Korean VLBI Network 129 GHz Band Polarizer

Abstract

A simulation for the design of a 90o differential phase shifter aimed toward Korean VLBI Network (KVN) 129 GHz band polarizer is described in this paper. A dual-circular polarizer for KVN 129 GHz band consists of a 90o differential phase shifter and an orthomode transducer. The differential phase shifter is made up of a square waveguide with two opposite walls loaded with corrugations. Three-dimensional electromagnetic simulation has been performed to predict the 90o differential phase shifter’s characteristics. The simulation for the differential phase shifter shows that the phase shift is 90o ± 3.3o across 108-160 GHz and the return losses of two orthogonal modes are better than -30 dB within the design frequency band. According to the simulation results the calculated performance is quite encouraging for KVN 129 GHz band application.

Keywords

• dual-circular polarizer
• differential phase shifter
• corrugated waveguide
• millimeter waveguide circuits
• radio astronomy receiver system