Proposal of bulk LTSA to realize low antenna impedance for real time millimeter wave imaging front-end

Active Millimeter-Wave (MMW) imaging is to be applied to security systems. Envelope phase detection (EPD) method will realize both short scanning time and low cost. The method uses an array of receiving antennas in combination with envelope detectors. We propose bulk linearly tapered slot antenna (LTSA) as the receiving antenna to realize low impedance. Unlike a conventional LTSA, a bulk LTSA antenna has low impedance due to its thick metallic fins. Since we detect input MMW directly, high circuit impedance often results in attenuation of envelope amplitude. The low-impedance LTSA avoids the attenuation. In this paper, we present the basic antenna characteristics and detection characteristics used with the EPD method, in particular the dependence of the fin thickness of the LTSA.