Antenna for Free Space-coupled Third-order Sub-harmonic Coherent Detector Array in the 300 GHz Band

A third-order sub-harmonic transmitarray is proposed for a coherent detector array. The transmitarray operates in the 100 and 300 GHz bands, which correspond to the RF signal and LO signals in coherent detection. Considering the integration with an on-chip detector element, the transmitarray element is fabricated on a silicon wafer utilizing a multi-layer photolithography process. In the measurement, the element shows the capability of receiving signals from its opposite sides in the dual-band. At 100 GHz the antenna emits broadside whereas in the 300 GHz band the beam radiates in the opposite direction.