Proposal for A Large Scale 1-D Subharmonic Coherent Detector Array in the 600 GHz Band

This paper presents an antenna model for scalable 1-D subharmonic coherent detector array operating at 600 GHz band. The signal from a 300 GHz local oscillator (LO) is fed into a waveguide with a slot array etched on the top surface. The waveguide slot array serves as an ultra-low loss LO power distribution network. The LO power is leaked out through the slot and collected by the on-chip detector antenna in the form of antenna-in-antenna near-field coupling. The detector antenna is a subharmonic transmitarray element (STE) which allows the LO and RF radiation coupled from different sides. It is modeled in TSMC 65 nm CMOS process that carries the field-effect transistor (FET) based detector. Dual-band conjugate matching is achieved between the FET and the STE. In the example of a 1 8 array, around 14 dB LO coupling efficiency is achieved in the simulation, which includes 9 dB power division loss. Moreover, the phase errors are negligible among the coupling paths.