A Meta-Grating-Enhanced Terahertz Subharmonic Mixer Operating at 0.31–0.35 THz

As operating frequencies rise, traditional subharmonic mixers face significant challenges due to high conversion losses, which limit their performance in terahertz applications. To address this limitation, we propose a terahertz subharmonic mixer enhanced by a meta-grating structure. This meta-grating is strategically loaded on the backside of the substrate and integrated with the subharmonic mixing circuit. The meta-grating structure substantially enhances the electric field intensity in the mixing region, improves the coupling efficiency between the input radio frequency (RF) signal and the Schottky diodes, and increases the RF signal utilization within the mixer, ultimately reducing conversion loss. Theoretical simulations and experimental results reveal that the proposed mixer achieves a typical single-sideband conversion loss of 13 dB in the 0.31–0.35 THz range, with a minimum conversion loss of 10.5 dB, outperforming conventional designs by a margin of 2 dB. This work presents a promising solution for achieving low conversion loss in terahertz subharmonic mixers, enabling advancements in terahertz communications and sensing applications.