A Horizontally Polarized Beam-Steerable Antenna for Sub-millimeter-wave Polarimetric Imaging and Collision Avoidance Radars

This paper presents the design, fabrication and evaluation of a novel horizontally-polarized frequency scanning large phased array antenna with high gain and very small form-factor. This antenna is intended for integration with a dual-polarized sub-millimeterwave radar for imaging and navigation applications. The concept is based on a travelling-wave structure composed of 440 cavity-backed patch antenna elements. The array generates a very narrow beam (similar to 2.5 degrees HPBW) with +/- 25 degrees steering capability. A prototype of the waveguide-fed slot-coupled patch array antenna is fabricated at 240 GHz using multi-layer silicon micromachining and is characterized using a near-field measurement setup at Y-band (i.e. 220-325 GHz). Measurement results, radiation pattern, HPBW, scan range, and gain, agree extremely well the design parameters. A minimum gain of 27 dBi over the desired scan range, and HPBW of less than 3 degrees and 10 degrees in azimuth and elevation planes, respectively, are measured.