Dual-Frequency Dual-Beam Reflectarray Based on Frequency-Division Duplexing Reflection Phase-Shifting Element

Former simultaneous dual-beam reflectarray (RA) designs employing frequency-division techniques suffer from limitations include inter-beam interference, reduced aperture efficiency, and restricted beam steering range. To address these problems, this letter presents a dual-frequency dual-beam Ku-band RA capable of simultaneous dual-frequency operation with independent control of the corresponding beams. The proposed RA is enabled by a frequency-division duplexing reflection phase-shifting element (FDRPE) that is formed by an integrated frequency-duplexing element (IFDE) with two independent reflective phase shifters. The IFDE adopts a slot-coupled feeding structure with integrated bandpass filters to realize frequency separation within a minimized footprint. A 16 × 16-element prototype was fabricated and characterized, demonstrating 2-D independent beam steering over the low band (LB, 10.4–11.2 GHz) and high band (HB, 13.9–14.7 GHz) with minimal inter-beam interference (angular deviation ≤ 0.5°, gain variation ≤ 0.5 dB). Measurements show that the array attains maximum aperture efficiencies of 21.6% and 20.6% for the low and high bands, respectively, and supports a 2-D ±40° 3-dB gain variation beam steering range in both bands. The proposed design enables effective simultaneous dual-beam operation, with good inter-beam isolation and improved beam steering range compared with its former counterparts employing frequency-division techniques.