Rectangular-loop slot antennas on substrate lenses for millimeter- and submillimeter-wave mixer applications

A rectangular-loop slot antenna, printed on the back surface of extended hemispherical lenses is examined as a candidate for millimeter- and submillimeter-wave integrated-circuit Schottky-diode mixers. The proposed configuration is based on coplanar waveguide (CPW) technology and incorporates a built-in integrated stub tuner (IST) to balance the geometry, help tuning the antenna and provide a DC return path for the mixing device. In order to design and optimize the antenna, a full-wave method of moments (MoM) technique has been developed for the input impedances. On the other hand, for the patterns through the lens, a geometrical-optics/diffraction theory approach is utilized. Simulation results compare well with commercially available software packages. The radiation characteristics of the proposed loop antenna, are optimized for integration with Schottky mixer diodes. The structure is well suited for implementing integrated planar mixers within the submillimeter-wave frequency spectrum.