Variable capacitor and filter circuit with bias voltage

• Main Authors: BANIECKI JOHN D, ISHII MASATOSHI, KURIHARA KAZUAKI, YAMANAKA KAZUNORI
• Format: Patent
• Language: English
• Published: 18.03.2014
• Subjects: BASIC ELECTRIC ELEMENTS; BASIC ELECTRONIC CIRCUITRY; CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES ORLIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE; ELECTRICITY; IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS

A variable capacitor includes a metal oxide film having a perovskite structure, first and second electrode films having the metal oxide film placed therebetween and to be coupled to an external voltage source, and a bias voltage source configured to provide a bias voltage that is applied in series or parallel to a capacitance of a capacitor including the metal oxide film and the first and second electrode films, wherein the bias voltage applied by the bias voltage source to the capacitance is adapted to maximize a voltage dependency of a relative permittivity of the metal oxide film.