A 1-Bit Bidirectional Reconfigurable Transmit-Reflect-Array Using a Single-Layer Slot Element With PIN Diodes

The design and experiment of a single-layer reconfigurable bidirectional antenna are presented for the first time, which combines the dynamic radiation characteristics of both reconfigurable transmitarray and reflectarray. The proposed element consists of a single-layer circular ring slot etched on one side of a dielectric substrate and two PIN diodes integrated across the slot. By turning them ON or OFF simultaneously, the induced current directions are reversed, thus achieving two phase states with 180° phase difference. The bidirectional radiation is achieved by utilizing the continuity of the cross-polarized electric field on the surface. A C-band 16×16 reconfigurable prototype with a side length of 400 mm is designed, fabricated, and measured. The measured results demonstrate the ability to electronically scan both the transmitted and reflected beams simultaneously. The measured gains of the transmitted and reflected beams at 5.35 GHz are 17.2 dBi and 15.4 dBi, respectively. The wideband 3-dB gain bandwidths are 32% for both the transmitted and reflected beams. The proposed design can achieve high-gain large-angle electronic scanning beams with distinctive advantages of being wideband, lightweight, low cost, and easy to fabricate and, hence, is suitable for bidirectional wireless communication applications.