BAND ELIMINATION FILTER

摘要

An inexpensive compact band rejection filter which realizes a high sharpness of a filter characteristic at ends of passbands and which has a large attenuation is provided. In the band rejection filter (1), at least one of elastic wave resonators which contributes to formation of a transition band has a propagation angle larger than those of the other elastic wave resonators. Accordingly, the at least one of the elastic wave resonators which contributes to the formation of the transition band has an electromechanical coupling coefficient smaller than electromechanical coupling coefficients of the other elastic wave resonator.