| 摘要 |
PROBLEM TO BE SOLVED: To provide a transformer capable of executing one of impedance conversion, coupling between a balanced circuit and a single end circuit, and electric isolation or over at an electric frequency in a range from UHF to microwave frequencies. SOLUTION: The film acoustically-coupled transformer includes a stacked pair of film bulk acoustic resonators (FBARs) and a stacked bulk acoustic resonator (SBAR) with an acoustic decoupler between the FBARs. Each FBAR has opposed planar electrodes with a piezoelectric layer between them. The film acoustically-coupled transformer additionally has first terminals electrically connected to the electrodes of one FBAR and second terminals electrically connected to the electrodes of the other FBAR. The film acoustically-coupled transformer provides 1:1 impedance transformation, can link single-ended circuitry with balanced circuitry or vice versa and electrically isolates a space between primary and secondary sides. COPYRIGHT: (C)2005,JPO&NCIPI |
