Design and analysis of optically controlled pattern reconfigurable planar Yagi-Uda antenna

A novel pattern reconfigurable planar optically controlled Yagi-Uda antenna is proposed. The antenna comprises a director, a driven dipole, a reflector and the substrate. The two parasitic elements loaded with positive intrinsic negative (PIN) photodiodes in the middle, applied as manipulating switches, are capable of varying the radiation pattern by transforming their physical structures. A prototype of the proposed antenna along with PIN photodiodes was fabricated to verify the concept of optically controlled pattern reconfiguration. The simulated and experimental results indicate that the |S₁₁| curves and radiation patterns of the proposed antenna in both the PIN switches' on and off state are similar; however, the direction of maximum radiation differs between these two states by 180°. Good unidirectional radiation patterns with the front-to-back ratios of 12 and 8 dB are obtained. About 10 dB impedance bandwidth can reach 15% and the maximum gain is more than 6.3 dBi. This study proposes a three-element equivalent current radiation model based on the current distribution from simulation, which can explain the directional radiation characteristics of the designed antenna well. This pattern reconfigurable antenna can be optically controlled remotely, reducing the effects of controlling network on the antenna radiator.