Full Wave Analysis of Microstrip Phase Shifter Printed on High Purity Ferroelectric Material

In this paper a detailed analysis of microstrip phase shifters which use ferroelectric material as active tuning element is performed, and results are compared with measured data. The phase-shift capability of the FEM results from the fact that the dielectric constant of such a material can be changed under the effect of an electric static bias field. Because of the nonlinear nature of these materials a static analysis is performed to obtain the spatial dependence of the pennittivity using an iterative numerical technique. Once the dielectric profile of the material is obtained, full wave analysis based on time domain technique is conducted to obtain the scattering parameters of the phase shifter. Excellent agreement between measured and computed data validates our approach. This allows for more complicated structures, such as a coplanar transmission line, to be analyzed using the same technique. This is a key step in the analysis of this type of phase shifters.