Miniaturized Phase Shifter Based on D-CRLH Resonator Using Phase Alignment Element

In this paper, a filter phase shifter based on D-CRLH resonator is proposed, which can not only provide constant phase shifting and filtering functions, but also has a compact structure and wide stopband rejection characteristics. Firstly, this paper adopts the D-CRLH structure as a single resonator to design the filter. This structure has a compact structure and multiple structural parameter variables, which makes this design have a high degree of freedom. Secondly, the resonance characteristics of the D-CRLH structure are analyzed by the equivalent circuit method, and the mapping relationship between the characteristics of the resonator and the equivalent circuit is established, which effectively shortens the design cycle. Finally, two band-pass filter branches are adopted to design the filter phase shifter, and the phase adjustment is carried out through the phase alignment element. Therefore, the designed phase shifter has better phase shift flatness while having the functions of phase shifting and filtering. The experimental results show that the center frequency of the phase shifter designed in this paper is 2.4 GHz, which can provide a phase shift value of 90° ± 2.6° in the frequency band of 2.13-2.6 GHz (fractional bandwidth is 19.58%).