| 摘要 |
PROBLEM TO BE SOLVED: To provide a variable capacitor which has a high Q value even in a high-frequency region and has a small rate of capacitance change due to a high-frequency signal while increasing its rate of capacitance change due to DC bias voltage. SOLUTION: The variable capacitor comprises a plurality of variable capacitance elements C1 to C5 which are connected in series and vary in capacitance due to DC bias voltage, and bias lines B11, B12, B21, and B22 which are connected to the variable capacitance elements C1 to C5 and fed with DC bias voltage. The variable capacitor is fed with a high-frequency signal of a predetermined frequency band. In the variable capacitor, the impedances of the bias lines B11, B12, B21, and B22 are higher than those of the variable capacitance elements C1 to C5 and do not substantially contribute to the Q values of the variable capacitor C1 to C5. The variable capacitor has a high Q value in a high-frequency region and has a small rate of capacitance change due to a high-frequency signal. COPYRIGHT: (C)2006,JPO&NCIPI
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