A microstrip-coupled slot-loop antenna for integrated receivers in the millimeter-wave band

A square-loop slot antenna, printed at the back surface of an extended hemispherical lens, is examined as a candidate for millimeter-wave (mm-wave) integrated-circuit Schottky-diode mixers. The loop slot is etched in a microwave substrate, and coupled to a microstrip line section printed on the other side of the substrate. A Schottky barrier diode shunted to ground is the mixing device. The input impedance of the antenna has been optimized to conjugate match the Schottky diode. To design and optimize the antenna, an efficient full-wave method of moments (MoM) technique, which solves the mixed potential integral equation (MPIE) in the stratified medium, has been developed. Patterns have been computed using the physical optics approximation and diffraction theory. The proposed configuration shows very wideband performance. Simulation results compare well with measurements. The proposed configuration is suitable to be scaled down for operation in the submillimeter-wave (submm-wave) band. © 1998 John Wiley & Sons, Inc.