| 摘要 |
PROBLEM TO BE SOLVED: To provide a voltage-controlled oscillator VCO that enables practical operation at a center frequency of 2 GHz band, has a sufficient frequency variable width and is made small in size in the VCO whose oscillating element is a piezoelectric bulk vibration element or a surface acoustic wave resonator. SOLUTION: This voltage-controlled oscillator(VCO) has an oscillation element, that is realized by a piezoelectric bulk vibration element or a surface acoustic wave resonator and a varactor element consisting of a ferroelectric or antiferroelectric thin film clamped by a couple of electrodes. The oscillating element and the varactor element are connected in series, and a control voltage applied to both terminals of the varactor element controls the impedance characteristic of the VCO.
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