High-Impedance Surface-Based Null-Steering Antenna for Angle-of-Arrival Estimation

A null-steering antenna with a high-impedance surface (HIS) to improve angle-of-arrival (AoA) estimation is designed and experimentally demonstrated. Because the HIS helps ensure that individual element patterns in an array are identical, the proposed antenna can perform null scanning with a low fluctuation without controlling the amplitude ratio of antenna elements. The simulation results demonstrate that the proposed antenna scans a null in the H-plane in 120° with greater than −30 dB from 2.4 to 2.6 GHz. Furthermore, both the measured S-parameters and element patterns agree well with the simulated results. Overall, the proposed antenna can successfully scan a null greater than −30 dB in 60° at a sampling frequency of 150 MHz.