Patent ID: 7414495
Filing Date: 2008-08-19
Classification: H03H

Abstract:
1. A balanced/unbalanced type coupled FBAR filter for performing conversion between a balanced signal and an unbalanced signal using FBARs, the balanced/unbalanced type coupled FBAR filter comprising: a first vibration section including an FBAR; a second vibration section including an FBAR and located parallel to the first vibration section; and a common vibration guaranteeing section, having the first and second vibration sections provided thereon, for commonly guaranteeing a vibration of the first vibration section and a vibration of the second vibration section so as to couple the two vibrations; wherein: the first vibration section includes: the second vibration section includes: an area size of the first lower electrode is generally equal to a total area size of the second and third lower electrodes and the area for isolating the second and third lower electrodes; an area size of the first upper electrode is generally equal to a total area size of the second and third upper electrodes and the area for isolating the second and third upper electrodes; and a part of the second lower electrode and a part of the second upper electrode are located to face each other.