Piezoelectric chip filter e.g. for mobile telephone, has three cavities for preventing interference of oscillations, with areas differing

摘要

The piezoelectric chip filter includes a spacer (8) between two piezoelectric substrates (1,2). The spacer includes an opening forming a cavity for preventing interference of oscillations of a two energy-limiting piezoelectric filter sections. A substrate is arranged on the surface of the first and second piezoelectric substrate respectively, forming two further cavities for preventing interference of oscillations. The area of at least one of the cavities differs from that of the remaining cavities. An Independent claim is included for a piezoelectric filter.