Optimal Configuration of Multi-Faceted Phased Arrays for Wide Angle Coverage

Abstract

As more users share the radio spectrum, communications systems become limited by interference. The situation can be improved by using smart antennas, including beam-scanning systems, for increased gain and interference suppression. The design of beam-scanning arrays typically involves a tradeoff between the coverage (the set of directions over which beams can be directed) and the scan angle. Wide coverage, which is typical for mobile communications, requires large scan angles from single arrays and this results in scan loss and greater cross-polarization which degrade the SNIR. Large coverage angles with low scan loss can only be realized with multi-faceted or conformal arrays. The multi-faceted arrays are simpler to manufacture. For hemispherical coverage, the basic array configurations are the pyramid and the pyramidal frustum. The design for the optimal geometry (face elevation angle) of pyramidal frustum arrays is addressed using a novel minimax-based approach and the methodology for the choice of the number of faces is presented. The coverage is the partial (rotationally symmetric) hemisphere. Applications for these wide coverage array systems are widespread, ranging from fixed and mobile satellite terminals, landmobile vehicular antennas, basestations for indoor and outdoor networks, to radar surveillance and radio astronomy.