A compact W-band quasi-optical detector packaged by meta-surface reflector and 3D-printed lens

This article presents a compact W-band quasi-optical detector that can be easily extended into an array for focal plane imaging applications. The quasi-optical detector consists of an antenna-coupled detector packaged by a low-profile meta-surface reflector and a 3D-printed lens. The antenna-coupled detector with a GaAs Schottky diode is printed on a low-cost and low-loss laminate. To extract the detected low-frequency signal within a small footprint, a pair of vertical metallic posts instead of conventional planar strips is designed and loaded at the ends of the antenna. For facilitating unidirectional radiation patterns, a low-profile meta-surface reflector with a thickness of lambda(g)/8 is placed under the antenna-coupled detector. In addition, a 3D-printed dielectric lens is loaded upon the antenna-coupled detector, which can enhance the radiation gain by 6 dB. Both the meta-surface reflector and the 3D-printed lens are fixed by an asymmetric H-shaped framework, forming a low-cost and lightweight package for the detector. Based on the proposed detector, a W-band 1 x 16 array is experimentally demonstrated, exhibiting a responsivity of 100 V/W similar to 410 V/W from 92 to 110 GHz. The total size of the array is only 27 lambda x 4 lambda x 1.8 lambda, where lambda is the free space wavelength at the center frequency.