Ceramic filter series (CERAFIL®) offers small and lightweight filters and traps that use the piezoelectric properties of ceramics to treat intermediate frequencies. CERAFIL® (ceramic filter) is a filter which uses a piezoelectric ceramics (barium titanate ceramics, leadzirconate- titanate ceramics, etc.) as an electric-mechanical transducer and as a mechanical resonator. It provides the electrical and the mechanical system simultaneously within a single element. When the piezoelectric ceramics is polarized by providing a pair of electrodes so that it can be excited in a prescribed vibrating mode, and if a suitable matching impedance is applied to operate it, a CERAFIL® is completed.