A 1-Bit Design for a Beam-Steering Reconfigurable Reflectarray Antenna in the Ku-Band

This work presents the system-level design, fabrication, and experimental validation of a 1-bit reconfigurable reflectarray with a 12×12 aperture operating at 15 GHz in the Ku-band. Each unit cell consists of a circular microstrip patch with four symmetrically arranged PIN diodes that are driven collectively to realize two reflection states with an approximately 180∘ phase difference near the operating frequency. The fourfold-symmetric unit cell exhibits similar reflection characteristics for x- and y-polarized incidence. The complete prototype combines four reusable 6×6 subarrays, a modular bias network, and an MCU-based controller that independently addresses all 144 unit cells. Measurements demonstrate beam steering from −50∘ to +50∘, a maximum measured gain of 17.9 dBi, an aperture efficiency of 17.8%, a cross-polarized level below −25 dB, and a 7.9% 1-dB gain bandwidth. The demonstrated combination of wide-angle beam steering, similar unit-cell characteristics for x- and y-polarized incidence, low cross-polarization, and reusable subarray construction provides a practical and scalable hardware approach for Ku-band wireless links, satellite communications, and radar systems.