Geometry-Dependent Performance of Ferroelectric Coplanar Waveguide Phase Shifters Based on Ba1-xSrxTiO3 Thin Films

To study the geometrical-factor-dependent microwave performance of a coplanar waveguide (CPW) phase shifter based on a (001)-oriented (Ba,Sr)TiO3 (BST) film, we fabricated CPW devices having various gaps and widths. The microwave dielectric properties of BST CPW phase shifter devices were examined by calculating the scattering parameter obtained using a HP 8510C vector network analyzer with a frequency range of 0.5 . 20 GHz at room temperature under dc bias fields of 0 . 40 V. The measured reflection loss and insertion loss at 10 GHz with no dc bias were about .18 .4 dB and .15 .2 dB, respectively, and mainly depended on the impedances of the CPW transmission lines. The measured differential phase shift values were about 30 120 at 10 GHz with a 40-V dc bias variation and depended on the gap size. KCI Citation Count: 2