Tunable, Metamaterial Based Ferrite Phase Shifter Design

In this paper, a rectangular waveguide phase shifter is introduced in X band. In order to benefit the metamaterial properties in this device, cooper wires are periodically printed on the substrate for composing effective electrical negative (ENG) permittivity and, the ferrite slabs are biased extraordinary for obtaining effective magnetic negative (MNG) permeability. By changing the phase shifter’s bias current, electromagnetic properties of ferrite are varied. Therefore, propagation constant of the wave, or in the other words, phase of the propagating wave is shifted, that results in tunable phase shifter design. According to the use of ferrite slabs in the extraordinary bias mode, to compose metamaterial medium, the structure suffers from high insertion loss disadvantage. One of the significant novelties of this paper is reducing the insertion loss which is achieved by MNG design method used in metamaterial phase shifter. Moreover, the proposed phase shifter benefits the miniaturization advantage of metamaterials, such that the phase shifting part of the device is reduced about 12 times regarded to the conventional phase shifters in the same frequency band. Bias circuit of the phase shifter is designed flexibly for both odd and even excitation modes. Also, according to the full wave CST software simulation results, almost twice phase shift of similar metamaterial phase shifters has been achieved.