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 crosspolarization 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.Index Terms-Smart antennas, antenna arrays, beam scanning, multibeam antennas, hemispherical coverage, scan loss, pyramid, pyramidal frustum.

Conformal antenna array for millimeter-wave communications: performance evaluation

“…A common solution for 360˚ area coverage is to use an array integrated on the four faces of a cube with two antennas realized on each face, such as in [5]. A different approach is presented in [6] where multi-faceted phased arrays are investigated. Other approaches are studied in [7] and [8], where conformal microstrip antenna arrays are presented for continuous conformal surfaces at 35 and 32 GHz.…”

Multi-facet AESA antenna with “tile” technology

“…In principle such a multi-facet array offers instantaneous electronic beam-steering over angles up to 360°, though most examples in the literature have the facets operating independently, so that each covers only a modest solid angle. For example, in a six-facet naval radar [3] five of the facets are disposed at 72° in azimuth with a slight upward tilt while the sixth facet points skywards, thus collectively achieving fair coverage of a complete hemisphere. A greater challenge is to operate adjacent facets coherently, such that the combined radiation pattern covers an exceptionally wide scan angle.…”

Array of spatial power combination for wide angle sector coverage

“…In cellular communication, sector antennas are widely adopted because they can cover a large service area without requiring alignment between the receiving and transmitting antennas . They are also widely used in tracking and surveillance, satellite on‐the‐move communications, and the shore early‐warning radar systems . Antennas with shaped beams are able to achieve sector coverage.…”