Integrated modified rectangular loop slot antenna on substrate lenses for millimeter- and submillimeter-wave frequencies mixer applications

A coplanar waveguide (CPW)-fed rectangular-loop slot antenna with built-in tuning and DC-return capabilities on extended hemispherical lenses is examined. The proposed configuration is scalable up to the submillimeter-wave frequencies. For designing and analyzing the impedance characteristics of the proposed antenna, a multilayer method of moments (MoM) solver has been developed based on the mixed potential integral equation (MPIE) formulation. The corresponding patterns through the lens are obtained using geometrical optics and the surface equivalence principle. Three models have been simulated and one of them has been built and tested at 65 GHz. The integrated antenna exhibits tuning capability, rotationally symmetric patterns, high directivity, good Gaussian coupling efficiency, and a reasonable bandwidth. In addition, computed results agree well with measurements and are used to characterize the input impedance and pattern behavior of the antenna.