Reflection-type ferroelectric phase shifter with defected ground structure

In order to obtain a low-loss ferroelectric phase shifter, we were designed and fabricated the reflection-type ferroelectric phase shifter with the defected ground structure (DGS) resonators. The ferroelectric phase shifter is consisted of a 3-dB 90degrees branchline hybrid coupler and terminated reflective circuit with tunable ferroelectric DGS resonator which can provide a high Q resonator characteristic at high frequencies. The design parameters of equivalent circuit for the tunable DGS resonator are derived by circuit analysis method and three-dimensional full wave finite element method. At 13.5 GHz, the fabricated phase shifter exhibited an insertion loss of better than 3.4 dB.