Monolithic Circular Transistor-Antenna Design for High-Performance Plasmonic Millimeter-Wave Detectors

This article reports a novel monolithic circular transistor-antenna by designing a ring-type asymmetric field-effect transistors (FET) itself as a receiving antenna element for high-performance plasmonic millimeter-wave detectors. Operation principle of the proposed device is discussed, focusing on how signal transmission through the ring-type structure is available without any feeding line between the antenna and the detector. To determine the antenna geometry aiming for a desired resonant frequency, we present an efficient design procedure based on periodic bandgap analysis combined with parametric electromagnetic simulations. From a fabricated ring-type FET-based monolithic antenna device for 120 GHz resonance frequency with the 3 dB full width at half maximum (FWHM) of 23 GHz, we demonstrated the highly enhanced optical responsivity 1.1 kV/W (× 5.5) and the reduced optical noise equivalent power (NEP) 18 pW/Hz^0.5 (× 1/7.4) at a chopping frequency of 2 kHz, compared to a reference bar-type detector. Moreover, the responsivity and the NEP in this article are in comparable order with the reported values of 2.2 kV/W and 14 pW/Hz^0.5, respectively, from the state-of-the-art CMOS-based antenna integrated direct detectors.