A 360° High-Resolution Single-Port Reflection-Type Phase Shifter for Reconfigurable Reflectarray Antennas

This letter presents a novel generalized single-port phase shifter topology utilizing a 360° high-resolution reflection-type phase shifter (RTPS), which can be applied for reconfigurable reflectarray antenna (RRA) applications. First, we propose a novel single-port RTPS topology for the first time. Compared with the traditional dual-port phase shifter topology, the proposed single-port phase shifter topology can be applied in RRA elements. Moreover, a detailed theoretical analysis is conducted by establishing an equivalent topology. Second, to improve design and test efficiency, we utilize the two-step phase extraction method. This method can reduce the required tunable states from 2²ⁿ to 2ⁿ⁺¹ for an n-bit varactor. Additionally, to minimize the phase step, a phase step optimization theory based on load optimization is proposed. Finally, to validate the design concept, a prototype was fabricated using low-cost PCB technology. By utilizing the two-step phase extraction method, the required tunable states for a 6-bit varactor are reduced by 97%. Experimental results show that the proposed 7-bit single-port RTPS achieves high resolution and a full 360° phase shift range with an insertion loss of 2.54 ± 1.24 dB at 2.45 GHz. Thus, the proposed single-port RTPS topology has the potential to be applied in RRA applications.