Phase Shifters With Wide Range of Phase and Ultra-Wideband Performance Using Stub-Loaded Coupled Structure

Compact planar phase shifters with wide range of differential phase shift across ultra-wideband frequency are proposed. To achieve that performance, the devices use broadside coupled structure terminated with open-ended or short-ended stubs. The theory of operation for the proposed devices is derived. To validate the theory, several phase shifters are designed to achieve a differential phase ranging from -180° to 180°. Moreover, three prototypes are developed and tested. The simulated and measured results agree well with the theory and show less than 7° phase deviation and 1.4 dB insertion loss across the band 3.1-10.6 GHz.