A 360° Low Phase Error Tunable Phase Shifter With High-Pass and Low-Pass Networks Based on SISL

This article proposes a novel 360° continuously tunable phase shifter employing a synergy of high-pass and low-pass networks. The analysis of the L-type high-pass and low-pass networks elucidates the correlation between phase shift and phase slope, alongside capacitance and frequency. Exploiting the divergent phase slope of high-pass and low-pass networks at different frequencies and circuit parameters, a 180° continuously tunable phase shifter with low in-band phase error is designed by utilizing the eight orders of high-pass and low-pass networks to compensate for each other. Further innovation yields a 360° phase shifter, achieved by integrating a 180° switch-type phase shifter (STPS) reliant on dual <inline-formula> <tex-math notation="LaTeX">$\pi $ </tex-math></inline-formula>-type pathways. The proposed phase shifter is fabricated and measured, confirming the efficacy of the proposed phase shifter, revealing a maximal in-band phase error of merely 4.98° within the 2.3–2.6 GHz. The incorporation of substrate-integrated suspended line (SISL) double-side inductors and capacitors consolidates its advantages, this phase shifter achieving a compact size which is only <inline-formula> <tex-math notation="LaTeX">$0.335\lambda _{{\text {g}}} \times 0.085\lambda _{{\text {g}}}$ </tex-math></inline-formula>.