On the use of a Rat-Race Coupler in the Design of a 180° Phase Shifter

Abstract

This paper investigates the use of a rat-race coupler in designing a reflection-type phase shifter with a 180° differential phase shift. The effects of the design parameters on performance are discussed; reported results demonstrate that bandwidths up to 27% with a phase error of ±2° can be obtained. Experimental results referred to a microstrip implementation on a FR4 substrate are also given.