Tunable microwave components based on KTa/sub x/Nb/sub 1-x/O/sub 3/ ferroelectric material

We made tunable microwave ferroelectric interdigital capacitors (IDCs) and resonators with different KTa/sub x/Nb/sub 1-x/O/sub 3/ (KTN) materials. Measurement results highlighted interesting variations, i.e. about 9.27% at 2 GHz on the capacitance value, at low bias voltage (/spl sim/15 kV/cm). This study enabled us to choose KTa/sub 0.5/Nb/sub 0.5/O/sub 3/ among three KTN compositions because, at room temperature, it showed the best properties for achievement of tunable devices. To our knowledge, among the few circuits based on a ferroelectric thin film other than Ba/sub x/Sr/sub 1-x/TiO/sub 3/ (BST) material, the ones we proposed demonstrate very promising performances for microwave applications. In the future, KTNs could compete with BSTs for tunable devices.