A horizontally polarized beam-steerable antenna for sub-millimeter-wave polarimetrie 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 (~2.5° HPBW) with ±25° 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° and 10° in azimuth and elevation planes, respectively, are measured.