LADDER-TYPE ELASTIC WAVE FILTER AND ANTENNA DUPLEXER USING SAME

摘要

This ladder-type elastic wave filter is characterized by the resonance frequency of a second parallel resonator being higher than the resonance frequency of a series resonator and lower than the anti-resonance frequency of the series resonator. By means of such a configuration, the attenuation pole resulting from the second parallel resonator is formed at a lower frequency region than the attenuation pole formed by the series resonator and at the higher frequency region side of the pass-band of the ladder-type elastic wave filter.