Analysis of sub-THz radiation detector built of planar antenna integrated with MOSFET

In this paper an approach to analysis of responsivity of MOSFET-based detectors of THz radiation has been presented. The authors have analyzed the substrate modes that affect performance of antennas that are always used as a part of detecting structures, and should be accounted for by proper choice of the substrate geometry. Then, a methodology to combine extracted properties of an arbitrary antenna with properties of the transistor channel has been described and employed to estimate responsivity of a detector built of a particular MOSFET integrated with several antenna structures. Finally, example detectors were fabricated and measured using sub-THz radiation sources operating in the combined bandwidth 220–360 GHz. Measurement results were compared with predictions which lead to conclusions on possible levels of the impedance of the transistor channel at these frequencies.