Low-Loss Self-Packaged Full Phase Shift Reflection-Type Phase Shifter Based on Hybrid Integrated Suspended Line Technology

A low-loss and self-packaged full phase shift reflection-type phase shifter (RTPS) based on the hybrid integrated suspended line (HISL) technology is introduced. The proposed RTPS consists of a 90° branch line coupler and two tunable parallel L–C loads connected to the through port and coupled ports. First, an enhanced two-step phase extraction method is proposed, reducing the evaluation state of the RTPS and achieving the minimal phase step while keeping the number of states unchanged. Second, the HISL technology is adopted in the design to achieve low insertion loss (IL). Due to the self-packaging characteristics of HISL, the proposed RTPS effectively avoids interference with surrounding circuits and is highly integrated. Third, the low-power digital tunable capacitor (DTC) with a bus interface is used as the tunable load, making the RTPS easy to integrate into large-scale phased array systems. Finally, a prototype is fabricated by using the sheet metal and PCB process. At the center frequency of 2.45 GHz, the proposed RTPS achieved a measured phase shift range (PSR) of 368° under 128 sweeping states with an IL of 0.9–1.6 dB, and the figure of merit (FoM) is 230°/dB.