Abstract: Acoustic wave devices are disclosed. The devices include a substrate, a bi-layer reflector and an acoustic wave resonator. The bi-electric reflector is above the substrate and includes a first layer that has a first acoustic impedance, and a second layer that has a second acoustic impedance lower than the first acoustic impedance. The first layer has a first surface that includes a floating region that provides a ceiling of a cavity. The second layer is on top of the floating region of the first layer. The acoustic wave resonator is on top of the second layer of the bi-layer reflector. The acoustic wave resonator includes a piezoelectric layer, an electrode and a counter-electrode such that application of a radio frequency voltage between the electrode and the counter-electrode creates acoustic resonance waves in the piezoelectric layer.

Abstract: Acoustic wave filter devices are disclosed. A device includes a layer providing or on a topmost layer of an acoustic reflector. The intermediary layer has a first region and a second region. The first region has a first layer thickness and the second region has a second layer thickness different from the first layer thickness. The device includes a first multilayer stack on the first region and a second multilayer stack on the second region of the intermediary layer. Each of the first and the second stacks includes a piezoelectric layer on a counter electrode that is located on the respective region, an input and an output electrode. Application of a radio frequency voltage between the input electrode and the counter electrode layer of the first stack creates acoustic resonance modes in the piezoelectric layer between the input and output electrodes of the first and the second stack.

Abstract: Acoustic wave filter devices are disclosed. A device includes a layer providing or on a topmost layer of an acoustic reflector. The intermediary layer has a first region and a second region. The first region has a first layer thickness and the second region has a second layer thickness different from the first layer thickness. The device includes a first multilayer stack on the first region and a second multilayer stack on the second region of the intermediary layer. Each of the first and the second stacks includes a piezoelectric layer on a counter electrode that is located on the respective region, an input and an output electrode. Application of a radio frequency voltage between the input electrode and the counter electrode layer of the first stack creates acoustic resonance modes in the piezoelectric layer between the input and output electrodes of the first and the second stack.

Abstract: Acoustic wave filter devices are disclosed. A device includes a layer providing or on a topmost layer of an acoustic reflector. The intermediary layer has a first region and a second region. The first region has a first layer thickness and the second region has a second layer thickness different from the first layer thickness. The device includes a first multilayer stack on the first region and a second multilayer stack on the second region of the intermediary layer. Each of the first and the second stacks includes a piezoelectric layer on a counter electrode that is located on the respective region, an input and an output electrode. Application of a radio frequency voltage between the input electrode and the counter electrode layer of the first stack creates acoustic resonance modes in the piezoelectric layer between the input and output electrodes of the first and the second stack.

Abstract: Acoustic wave filter devices is disclosed. The device includes a piezoelectric layer, an input electrode and an output electrode located on a top surface of the piezoelectric layer and physically separated from one another, and a counter electrode having a top surface connected to a bottom surface of the piezoelectric layer. The input and output electrodes each include a base and at least one extension extending from the base. The at least one extension of the input electrode extending alongside and in a generally opposite direction to and separated by a gap width from an adjacent extension of the at least one extensions of the output electrode. In some embodiments, the at least one extension of the input or output electrodes has a width that can changes from a first end of the at least one extension to a second end.

Abstract: An acoustic wave filter device is disclosed. The device includes an acoustic wave filter element, and a first resonator and a second resonator coupled to the acoustic wave filter element. The acoustic wave filter element includes interdigited input electrodes and output electrodes located on a top surface of a piezoelectric layer and an counter-electrode on the bottom surface of the piezoelectric layer. Each of the first and the second resonators includes a resonator electrode on the top surface of the piezoelectric layer and a resonator counter-electrode on the bottom surface of the piezoelectric layer. The first resonator has a first notch in resonator impedance at a first frequency. The second resonator includes a first mass loading layer on the second resonator electrode such that the second resonator has a second notch in resonator impedance at a second frequency that is different from the first frequency.