Broadband differential phase shifter using vertically installed coupled structure

This paper presents a novel broadband phase shifter based on a vertically installed coupling structure that enables the practical realization of tightly coupled sections. The configuration to implement broadband phase shifters using a simple coupled section is first analyzed theoretically. The design parameters can then be obtained according to the desired phase shift from these analytic formulas. The vertically installed coupled structure is modified to eliminate existing limitations that restrict the implementation in broadband phase shifters. For demonstration purposes, a 45° phase shifter is designed, fabricated and measured to give good performance over a bandwidth of 100%.