Abstract
In this letter, we present a novel compact waveguide filtering twist
that can be readily fabricated from metal using the computer numerical
control (CNC) machining process. This filtering twist is comprised of
four coupled resonators which are rotationally deformed to provide the
desired 90-degree twist. Such resonator structures eliminate the use of
curved features and therefore are ideally suitable for conventional CNC
machining. The proposed design offers appealing advantages including
great compactness, easy fabrication, and good scalability to
millimetre-wave and terahertz frequencies. The design is demonstrated at
X-band and has a fourth-order Chebyshev filter response (bandwidth 0.4
GHz, centred at 10 GHz). The good agreement between simulation and
measurement results validates the proposed concept.