BULK ACOUSTIC WAVE RESONATOR WITH TWO PIEZOELECTRIC LAYERS AS BALUN IN FILTERS AND DUPLEXERS

摘要

A bulk acoustic wave device (20) having two resonators (92, 94) in a stacked-up configuration separated by a dielectric layer (50). The device (20) can be coupled to a lattice filter or a ladder filter to form a passband filter with an unbalanced input port (41) and two balanced output ports (16, 18). One or more such passband filters can be used, together with another lattice or ladder filter, to form a duplexer having an unbalanced antenna port, two balanced ports for one transceiver part and two balanced ports for another transceiver part.