Wideband Phase Shifter With Wide Phase Range Using Parallel Coupled Lines and L-Shaped Networks

A planar broadband phase shifter with wide range of differential phase is proposed. To achieve this performance, the design uses quarter wavelength parallel coupled lines combined with two L-shape networks. The L-shaped network includes a short-ended stub and a section of transmission line as an impedance transformer. The value of the differential phase can be adjusted through varying the coupling coefficient of the coupled lines along with the length and impedance of the short-ended stubs and transformer. The theory of operation for the proposed design is explained. To validate the theory, a phase shifter is designed and manufactured to realize 180 degrees differential phase. The simulated and measured results agree well with the theory and show less than b degrees phase deviation and 1.3 dB insertion loss across the band 1-3 GHz.