Design and evaluation of a novel antenna array for azimuthal angle-of-arrival measurement

This paper describes a novel antenna array concept in which a "Y"-shaped distribution of elements is used to achieve uniform angle-of-arrival (AOA) measurement performance in azimuth, and a ground plane is employed to reduce the potential for confusion due to scattering from nearby structures and interference from low elevation angles. A simple method for field calibration of this array is also presented. A prototype has been built and tested in field conditions at 460 MHz. Using maximum likelihood estimation, the array is able to resolve single AOAs to within a few degrees and is able to identify discrete multipath from the same source. A shortcoming of the field-tested design is that it has poor gain along the horizon, due to edge diffraction from the ground plane. To control this diffraction, an elliptical rolled edge termination is proposed. It is shown that a rolled edge increases the horizon gain by 5 dB while maintaining high suppression at low elevations and maintaining a low physical profile.