PLANAR DETECTORS FOR MULTIELEMENT SYSTEMS OF MILLIMETER-WAVE IMAGING

We discuss the concept of developing a millimeter-wave multielement matrix receiver on the basis of planar antennas with directly coupled low-barrier Schottky diodes. Three main problems are considered which involve choosing and developing a design of the planar antenna coupled with the low-barrier Schottky diode, optimizing the parameters of the low-barrier Schottky diodes for obtaining maximum sensitivity, and ensuring compact arrangement with weak mutual influence of the planar detectors in a two-dimensional array. We propose a design of the slot antenna with an active resistance of about 800 Omega at a resonant frequency of 94 GHz. The detection characteristics of diodes with the differential Schottky-barrier resistance in the range R-j = 0.4-1000 k Omega for a zero bias are studied experimentally. The mutual influence of the neighboring antennas is examined for developing the multielement radio-imaging system. The conditions of weak cross influence of the closely located planar detectors are determined.