Oscillator with voltage control

Abstract

The technique subject of the invention is to provide a kind of voltage-controlled oscillator, which has very large variable frequency range, high frequency-stability, low phase noise, very little change after a long period, ultra-small type, and the capability of simultaneously performing oscillation operations of plural frequencies. The film bulk acoustic resonator uses the single crystal ferroelectric, which has the same pole direction as the film thickness direction and a thickness smaller than 10 mum, as the piezoelectric body. By changing the voltage added to the electrode, a voltage-controlled oscillator having a large oscillation frequency variation rate larger than 0.01%/V and very small phase noise is provided.

Description

technical field [0001] The invention relates to a voltage controlled oscillator. Background technique [0002] In recent years, voltage controllers using thin-film piezoelectric resonators have attracted attention. A thin film piezoelectric resonator (FBAR: Film Bulk Acoustic Wave Resonator) is an element in which a lower electrode, a piezoelectric film, and an upper electrode are sequentially formed in a cavity formed on a substrate. [0003] Such a thin-film piezoelectric resonator resonates at a frequency under the condition that the total thickness of the lower electrode, the upper electrode, and the piezoelectric film in contact with the air layer is half the wavelength of the oscillation wavelength. At a frequency of 1 GHz to 5 GHz, the thickness corresponds to a thickness of about 0.5 μm to 3 μm. This is particularly advantageous for resonance in the high-frequency region above GHz. [0004] Figure 27 The impedance change around the resonance frequency of such a t...

AI Technical Summary

Problems solved by technology

However, since the Q value of the reactance element is very low, there is a problem that the Q value of the voltage controlled oscillator further dec...

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