LC-Enhanced CMOS Plasmonic Detector for Sub-Terahertz Imaging

An $LC$ -enhanced plasmonic detector for sub-terahertz (sub-THz) imaging is presented, fabricated using a standard 0.18- $\mu $ m CMOS process. The detector adopts a differential topology with cross-coupled capacitors and incorporates drain inductors, which form $LC$ paths that enhance high-frequency signal transfer and increase the drain impedance. This configuration strengthens fundamental coupling while attenuating low-frequency noise components. In addition, the inductors provide an impedance-loading effect, increasing the drain impedance, which boosts both the output voltage swing and voltage responsivity. The fabricated detector occupies a compact die area of $0.79\times 0.70$ mm². Measurement results demonstrate a peak voltage responsivity of 1561 kV/W and a minimum noise equivalent power of 11.6 pW/ $\surd $ Hz at 150 GHz. Sub-THz imaging experiments achieve a signal-to-noise ratio of 29.2 dB, validating the effectiveness of the detector for high-resolution, low-noise passive imaging applications.