3D printed waveguide step-twist with bandpass filtering functionality

Abstract

A novel waveguide step-twist integrated with a bandpass filter is presented in this Letter. The twist is composed of four equally rotated cavities to achieve polarisation rotation and filtering functionalities simultaneously. Such step-twist can achieve a significant reduction in size and weight. The design is demonstrated at Ka-band using waveguide technology and is fabricated using a stereolithography apparatus 3D printing together with metal plating. The device is designed to have a centre frequency of 32 GHz and a bandwidth of 1 GHz. The measured result shows good agreement with simulations, with a measured average insertion loss of 0.84 dB and a return loss better than 15 dB across the passband.