Wideband 90 degrees phase shifter using modified composite resonant circuits for phase slope alignment

Abstract

This article proposes a new wideband 90 degrees phase shifter, aligning the phase slope between a reference line and a mainline to reduce the slope deviation. The design theory of the proposed phase shifter using a modified composite resonant circuit is converted from the LC resonant circuit to the transmission line for easy fabrication. To validate the design theory, the conventional and proposed phase shifters are designed, fabricated, and measured. The fractional bandwidth of the proposed phase shifter is over 77% in terms of the magnitude and phase difference. Therefore, the measurement results agree well with the design theory within a 0.5 dB insertion loss and +/- 10 degrees phase deviation, except for fabrication errors.