Abstract: An acoustic resonator device, filter devices, and methods of making the same. An acoustic resonator device includes a substrate having a surface and a single-crystal piezoelectric plate having front and back surfaces, where the back surface is attached to the surface of the substrate except for a portion of the piezoelectric plate forming a diaphragm that spans a cavity in the substrate. The device further includes an interdigital transducer formed on the front surface of the piezoelectric plate, where interleaved fingers of the IDT disposed on the diaphragm are configured such that a radio frequency signal applied to the IDT excites a primary shear acoustic mode in the diaphragm. The interleaved fingers include a first layer adjacent the diaphragm and a second layer over the first layer, the second layer having a narrower width than the first layer.

Abstract: An acoustic resonator is provided that includes a substrate; a piezoelectric layer having a portion that forms a diaphragm over a cavity; and IDT on the piezoelectric layer that includes a first conductor level including first and second busbars disposed on respective portions of the piezoelectric layer, a first set of elongated fingers extending from the first bus bar onto the diaphragm, and a second set of elongated fingers extending from the second bus bar onto the diaphragm, the second set of elongated fingers interleaved with the first set of elongated fingers. The acoustic resonator also includes a second conductor level over the piezoelectric layer and covering at least portions of the first and second busbars.

Abstract: A valve assembly defines a chamber and three ports. A first valve selectively obstructs a first port to prevent fluid communication between a secondary air injection pump and the chamber. A second valve selectively obstructs a second port to prevent fluid communication between an air intake manifold and the chamber. A third port provides fluid communication between the chamber and an exhaust manifold. The chamber thus serves as a common passageway for secondary air flowing from the pump to the exhaust manifold and for exhaust gas flowing from the exhaust manifold to the air intake manifold. In a preferred embodiment, the first and second valves are rigidly interconnected.