| 摘要 |
A thin film capacitor includes a pair of electrodes and a dielectric layer having piezoelectricity sandwiched therebetween. The phase characteristic of an impedance resulting from application of a voltage to the pair of electrodes peaks periodically according to a frequency of a signal to be inputted or outputted. The frequency of the signal is adjusted to fall in between the values representing the adjacent peaks. Since there are periodic peak values that depend upon the frequency of the inputted or outputted signal, in fabricating a band-pass filter, a higher attenuation can be attained by ensuring that the peak value stands at a low-frequency level. Thus, a higher attenuation can be attained at low frequencies without sacrificing the band-pass characteristic, whereby making it possible to produce a band-pass filter that is excellent in band-pass characteristic.
|
