A Novel terahertz Wave Microstructure Phase Shifter Loaded in Rectangular Waveguide

Abstract

This paper proposes a novel, compact and wide phase shift range tunable phase shifter operating in 0.3THz-0.325THz, which is loaded in WR-3 band rectangular waveguide and controlled by electricity. The phase shifter comprises of three phase shift units that are mounted in the H-plane cuts of the rectangular waveguide. The phase shifter units based on quartz substrate are designed to be a symmetrical structure for both increasing volume of phase shift and reducing the insertion loss. Each unit is adopted microstripe line as secondary transmission line coupling with primary transmission line inside rectangular waveguide via gold probe to introduce extra parallel impedance into main transmission line. Furthermore, diodes are loaded with secondary transmission line for electric steering so that the phase shifter with total three phase shift units is capable to realize four discrete phase shifts. Simulation results show the phase shift ranges from $\pmb{0}$ to 180 degrees with the step of 60 degrees. Its insertion loss is better than −1.5dB, and the return loss is below −10dB. A prototype has been fabricated and measured by using the terahertz vector network analyzer. In static test, the maximum phase shift is up to 260 degrees. For the dynamic test of the three shifting units, the maximum phase shift is about 90 degrees at 0.31THz.