A W-band trans-twist monopulse microstrip patch reflectarray

The design and performance results of a W-band trans-twist microstrip patch reflect-array excited by a multi-mode corrugated horn feed is described in this paper. The reflect-array performs dual role of collimating the beam as well as twisting the polarization. The multi-mode corrugated horn is used as a feed to generate sum, azimuth and elevation difference patterns. This paper also points out the systematic aperture phase errors in design due to non-availability of conjugate pair of patch dimension that simultaneously delivers required focusing and twisting. A few reflect-arrays were fabricated and tested at W-band. The measured performance showed high gain and low cross-polarization and very good monopulse patterns. The performance is very good, repeatable and close to the expected specifications.