An Electromagnetic-Mechanically Co-Designed F-Band Mixer Using Metal-Integrated Suspended Line Technology

This article presents a systematic electromagnetic (EM)-mechanical co-design methodology based on metal-integrated suspended line (MISL) technology. The method is demonstrated through the design, fabrication, and experimental validation of an F-band mixer. Due to the absence of a supporting substrate in MISL, incorporating the specific mechanical support design is indispensable to ensure mechanical stability. To address this challenge, the innovative approach in this article fully leverages the dual functionality of the short-circuit structures within filters in the mixer for both filtering and support. This eliminates the dependency on additional support structures, thereby reducing redundant circuit area usage and associated insertion loss. By establishing an EM-mechanical bi-objective evaluation function, both the intermediate frequency (IF) and local oscillator (LO) filter structures were designed and optimized. For the first time in terahertz circuit design, mechanical reliability is incorporated from the initial design stage. Experimental results demonstrate that the mixer exhibits conversion losses ranging from 5.48 to 7.72dB across 113–120 GHz, which aligns well with simulation curves, demonstrating competitive radio frequency (RF) performance and verified mechanical fabrication reliability. This approach provides a new solution for terahertz circuit packaging and MISL circuit design, achieving high performance and miniaturization.