A Balanced Digital Phase Shifter by a Novel Switching-Mode Topology

Abstract

A balanced digital phase shifter by a novel switching-mode topology is proposed. A 3-bit balanced digital phase shifter is given as an example, the working bandwidth of which is from 2.3 to 2.7 GHz. The proposed 3-bit balanced phase shifter comprises two balanced loaded-line phase shifters (90 degrees and 45 degrees) and six twist-line broadband 180 degrees phase shifters. The balanced loaded-line digital phase shifter changes phases while the even-or odd-mode signal is excited. The 180 degrees phase shifter controls the balanced signal to be even or odd mode. The commensurate transmission line filter is used as the biasing circuit.