Voltage tunable varactors and tunable devices including such varactors

A tunable fin line filter comprising:

• a rectangular waveguide;
• three conductive plates positioned along a longitudinal axis of the waveguide, wherein one of said conductive plates is insulated from said waveguide;
• two lateral plates having shorted end fin line resonators and being grounded to the waveguide;
• plurality of varactors, one of said varactors being electrically coupled to each of fin-line resonator;
• wherein the tunable varactor includes a substrate having a first dielectric constant and having generally planar surface, a tunable ferroelectric layer including a tunable component and a non-tunable component and being positioned on the generally planar surface of the substrate, the tunable ferroelectric layer having a second dielectric constant greater than said first dielectric constant, and first and second electrodes positioned on a surface of the tunable ferroelectric layer opposite the generally planar surface of the substrate, said first and second electrodes being separated to form a gap therebetween, said voltage tunable dielectric varactor having a Q factor from about 50 to about 10,000 when operated at frequencies ranging from about 1 GHz to about 40 GHz.