Low‐cost and easy‐to‐embed 7‐bit 360° phase shifter with transitions for large‐scale phased arrays

Abstract

AbstractIn this letter, a low‐cost and easy‐to‐embed 7‐bit 360° phase shifter with transitions is presented for applications to beamforming in the large‐scale phased array. In the proposed 360° phase shifter, the topology of the reflection‐type phase shifter (RTPS) is employed, composed of a 3‐dB branchline coupler terminated with two tunable parallel L–C loads. First, a two‐step phase extraction process for RTPS is applied to design the RTPS rapidly with competitive performance, including 360° phase range and low insertion loss. A huge amount of parameter sweep is reduced in the design and test. Meanwhile, the parameter of inductors in the tunable loads is investigated effectively, to achieve the minimal phase step. Second, aiming at the enhanced performance of beamforming and improved flexibility of integration, the stripline is adopted in the design of the phase shifter, avoiding the interference on antenna radiation effectively. To facilitate the integration with antenna and radio frequency connectors of the input and output signals, a stripline‐to‐microstrip line transition with electromagnetic bandgap structures is adopted. By this means, the complexity and cost of fabrication are decreased. Finally, fabricated in the low‐cost printed circuit board technology, our proof‐of‐concept design operated from 2.4 to 2.5 GHz is measured and achieves a 386.8° phase shift range with an insertion loss of 2.21 ± 0.82 dB at 2.45 GHz.