Ultra-Wideband 90° Waveguide Twist for THz Applications

We report on the design, fabrication, and characterization of a novel 90 degrees waveguide step twist with 56% fractional bandwidth. The proposed twist provides 90(?degrees) field rotation in the frequency range 210-375 GHz. The experimental results are in good agreement with the electromagnetic simulations showing an insertion loss below 0.3 dB and a return loss better than 20 dB over most of the band. The ultra-wideband performance, tolerance to fabrication inaccuracies, and compactness makes the proposed design attractive for various mm and submillimeter applications. The twist geometry is optimized for simple fabrication through direct milling. Furthermore, the design remains highly compact since both steps are fabricated on a single washer.

Automated summary

We present a novel 90 degrees waveguide step twist with 56% fractional bandwidth, which provides field rotation at frequencies ranging from 210 to 375 GHz. Experimental results agree well with electromagnetic simulations, showing low insertion loss below 0.3 dB and excellent return loss better than 20 dB over most of the band. The design is attractive for various mm and submillimeter applications due to its ultra-wideband performance, tolerance to fabrication inaccuracies, and compactness.