Single-Antenna Direction Finding With Harmonic Analysis Based on Phasor Beam-Steering Antenna

A novel single-antenna azimuthal direction-finding (DF) method with harmonic analysis is proposed in this letter. Leveraging the Phasor Beam Steering (PBS) antenna's capability of reconfiguring both the amplitude and phase patterns, a one-to-one relationship between the incident angles and the amplitude ratio, as well as the phase difference of the received signal in two working states, can be established. Then a phasor composed of the amplitude ratio and phase difference can be obtained simply by analyzing the received signals' harmonics. Hence, the DF can be realized through the lookup table method. Unlike the conven-tional DF method with at least two antennas, the proposed method only requires a single antenna, simplifying the DF system effectively and reducing DF errors caused by electromagnetic coupling between antennas. Moreover, compared with common single-antenna DF, this method eliminates the need for single-antenna rotation, simplifies the radio frequency channel structure to a single channel, and reduces the computational complexity. Numerical results are provided to demonstrate the effectiveness of the proposed method, and an azimuthal single-antenna DF system working at 5.87 GHz is tested to verify its feasibility.