An antenna arrangement for phase comparison monopulse DOA estimation using nonuniform planar array

A distributed array radar with a very large aperture can provide high angle resolution by its very narrow beam. In this radar, nonuniform antenna arrangement might be used to suppress grating-lobes caused by long distance between element antennas. For estimation of direction-of-arrival, a phase comparison monopulse techniques, which is established and widely-used simple method, is considered in this paper and we revisited it for a distributed radar. The purpose of this paper is to realize a phase comparison monopulse estimation on a nonuniform planar array antenna as simple as on an uniform planar array antenna. In this paper, we formulate the problem of phase comparison monopulse on a nonuniform planar array antenna that a monopulse estimation can not be applied independently to elevation and azimuth angle, and propose an antenna arrangement rule to solve this problem. Evaluation results indicate that the proposed rule can avoid the dependency on undesired angle for monopulse estimation.