Circular Polarized Antennas With Harmonic Radar: Passive Nonlinear Tag Localization

Abstract

This research proposes a high performance, low-profile planar design, and demonstration of circularly polarized harmonic antenna arrays for 4 and 8 GHz harmonic radar system which is equipped, and the antenna's circular polarization performance is tested using a passive non-linear harmonic tag (snowflake) in a noisy environment. This work mainly concentrates on investigation of the wave polarization (Circular), gain estimation and impedance matching of the antenna arrays that will be potentially assembled to the 2 nd order harmonic radar system operating at 4 and 8 GHz, which plays a critical role in 2-D tag localization and post processing methods. The passive snowflake tag design is implemented in the simulation to determine the current distribution and gain plot patterns in comparison to a classic dipole antenna tag structure. In experiments: a combination of fundamental circular polarized (Left-hand) antennas were demonstrated to find Axial Ratio (A.R.) ≤ 3 dB band. A novel tag 2-D localization measurement, combination of CP harmonic antenna arrays is utilized to perform and obtain the circular polarized received signal power in dBm v/s angle rotation by every 10° on a rotating platform setup. Finally, the wireless tag tracking result is achieved by using the designed circularly polarized antennas and the passive non-linear tag orientation setup.