Dielectric based frequency agile microwave devices

Low loss highly tunable microwave material can be fabricated using dielectric laminate structure in which effective dielectric constant ε_ef is efficiently controlled. The proposed combined structure usually consists of two dielectric parts with an air gap between them. This gap has to be arranged in such a way that provides the largest perturbation in the electromagnetic filed. By means of fast piezo electric mini-actuator, the size of the air gap is changed. As a result, the ε_ef of given structure strongly varies that is used for device control. Wideband low loss waveguide phase shifters, highly tunable dielectric resonators, and based on them 20%-tunable filter are realized experimentally.