A 410-GHz Detector using AC-coupled Substrate-Integrated Waveguide Slot Antenna in CMOS

In this paper, a 410-GHz detector is designed using an AC-coupled on-chip substrate-integrated waveguide (SIW) slot antenna in a 65-nm CMOS process. The antenna shows simulated radiation efficiency of 35% and −10-dB bandwidth of 20 GHz at 410 GHz. Since SIW structures are DC-shorted in the sidewall, additional AC-coupling structures are necessary for circuit integration. In this work, an AC-coupling structure is implemented by exploiting the antenna sidewall as a metal-oxide-metal capacitor without increasing the size or introducing additional loss. A diode-connected NMOS transistor is used to design the detector. The detector exhibits simulated voltage responsivity of 316 V/W and noise equivalent power of 37 pW/√Hz at 410 GHz, demonstrating AC-coupled SIW slot antenna can be employed for THz detection.