Development of 90-deg Differential Phase Shifters using Corrugated Waveguide Structure for KVN Dual-Circular Polarizers
Moon-Hee Chung, Do-Heung Je, Sooyeon Kim, and Seog-Tae Han
The dual-circular polarizer of KVN 86 GHz receiver consists of a 90-deg
differential phase shifter and an OMT(orthomode transducer).
The symmetric OMTs generally show wideband performance but narrow
bandwidth of the current phase shifter employing dielectric slab of KVN
86 GHz receiver limits broadband operation of the dual-circular polarizer.
For the purpose of widening the KVN 86 GHz receiverʼs observation
bandwidth, a 90-deg differential phase shifter with dual-depth corrugated
waveguide structure has been developed for 84~115 GHz band.
The simulation results showed more than 30 % bandwidth for axial ratio of
0.5 dB across the design frequency band. Before manufacturing the 90-deg
differential phase shifter for 84~115 GHz band, a Q-band scale model of
90-deg differential phase shifter has been fabricated using direct machining.
Measurement of Q-band differential phase shifter showed around 32 %
bandwidth for 90 ±3.3 deg corresponding to 0.5 dB axial ratio.
The measurement agrees well with the simulation result. In this presentation,
design and measured results of 90-deg differential phase shifters for KVN
receivers will be presented and further applications will be also discussed.