On the Assessment of Antenna Patterns for Wideband Amplitude-Only Direction Finding

An approach for assessing the quality of antenna patterns for wideband unambiguous amplitude-only direction finding (AODF) at millimeter waves with two squinted antennas is discussed. Several parameter criteria are proposed to evaluate the radiation performance of the standalone antenna element in terms of pattern smoothness and beamwidth stability with frequency. A computational analysis of these criteria is conducted to identify the needed parameters of a considered (horn) antenna suitable for resilient AODF performance. For experimental demonstration, an AODF horn antenna subsystem is constructed as a single all-metal three-dimensional (3-D) printed structure with standard waveguide feed ports. The passive front end performs as expected, where a maximum error of ±1°/dB is maintained across a scanning field of view (FoV) from -20° to +20° over the entire W-band. The proposed design methodology can be generalized to E-plane patterns and different antenna types as suitable for a specific application.