A Low-Profile Direction-Finding Antenna with Deep Null Steering Using High-Impedance Surface

This paper proposes a null-steering antenna that scans a deep null without controlling the amplitudes of the antenna elements. The proposed antenna comprises two dipole antennas and a reflector made by a high-impedance surface (HIS). The antenna characteristics are compared to a conventional patch antenna array to demonstrate that the proposed one is more suitable for a direction-finding antenna. The study clarifies that the HIS makes the antenna height as low as the patch antenna and null depths greater than –30 dB within ±70°. The antenna can be potentially integrated into simple and accurate direction-finding systems due to its compactness and excellent scanning performance at a low cost.