A systematic approach towards the design of multimode quasi-integrated horn antennas for receiver applications

A systematic approach has been developed for the design of multimode pyramidal horn antennas for quasi-optical receiver applications. The method is applied to the design of quasi-integrated horn antennas at millimeter-wave frequencies with a gain in the range of 18-25 dB, a fundamental Gaussian coupling efficiency around 97%, and a 10% bandwidth. The design criterion chosen is the maximization of the fundamental Gaussian coupling efficiency, and the corresponding necessary conditions are determined directly from the aperture fields. Also, for the analysis of the gradually flared gain-enhancing and phasing section, an improved technique is introduced which accounts for mode conversion. The optimized design is tested by performing a final full-wave analysis on the structure, using the generalized scattering matrix technique, and by pattern measurements at 91 GHz and 370 GHz.<>