Patent ID: 8183959
Filing Date: 2012-05-22
Classification: H01G,H03H

Abstract:
1. A variable capacitance circuit in which capacitance is controlled, comprising: a first variable capacitance section; and a second variable capacitance section; wherein the first variable capacitance section comprises a first variable capacitance element unit including n pieces, where n is a natural number of two or more, of variable capacitance capacitors connected in series in view of a first high frequency flow path and in parallel in view of a first direct current flow path, and the variable capacitance capacitors comprises one or more variable capacitance elements, each of which includes a dielectric layer having a dielectric constant varying according to a first applied direct-current voltage, and a pair of electrodes sandwiching the dielectric layer therebetween, and wherein the second variable capacitance section comprises a second variable capacitance element unit which has an applied voltage amplitude smaller than a voltage amplitude of high frequency signal applied to the first variable capacitance element unit, and the second variable capacitance unit comprises one or m pieces, where m is a natural number smaller than n, of variable capacitance elements connected, each of which includes a dielectric layer having a dielectric constant varying according to a second applied direct-current voltage and a pair of electrodes sandwiching the dielectric layer therebetween.