A method for designing a narrowband acoustic wave microwave filter including: generating a modeled filter circuit design having circuit elements including an acoustic resonant element defined by an electrical circuit model that includes a parallel static branch, a parallel motional branch, and one or both of a parallel Bragg Band branch that models an upper Bragg Band discontinuity and a parallel bulk mode function that models an acoustic bulk mode loss; and generating a final circuit design. Generating the final circuit design includes optimizing the modeled filter circuit design to generate an optimized filter circuit design; comparing a frequency response of the optimized filter circuit design to requirements; selecting the optimized filter circuit design for construction into the actual acoustic microwave filter based on the comparison; and transforming the optimized filter circuit design to a design description file for input to a construction process.

Filter devices and methods are disclosed. A filter device includes a substrate and a piezoelectric plate attached to the substrate, the piezoelectric plate forming diaphragms spanning respective cavities in the substrate. A first portion of the piezoelectric plate has a first thickness. A front surface of a second portion of the piezoelectric plate is recessed relative to a front surface of the first portion of the piezoelectric plate such that the second portion of the piezoelectric plate has a second thickness less than the first thickness. A conductor pattern is formed on the front surfaces of the first and second portions of the piezoelectric plate. The conductor pattern includes a first interdigital transducer (IDT) with interleaved fingers on a diaphragm having the first thickness, and a second IDT with interleaved fingers on a diaphragm having the second thickness.

Filter devices and methods are disclosed. A filter device includes a substrate and a piezoelectric plate attached to the substrate, the piezoelectric plate forming diaphragms spanning respective cavities in the substrate. A first portion of the piezoelectric plate has a first thickness. A front surface of a second portion of the piezoelectric plate is recessed relative to a front surface of the first portion of the piezoelectric plate such that the second portion of the piezoelectric plate has a second thickness less than the first thickness. A conductor pattern is formed on the front surfaces of the first and second portions of the piezoelectric plate. The conductor pattern includes a first interdigital transducer (IDT) with interleaved fingers on a diaphragm having the first thickness, and a second IDT with interleaved fingers on a diaphragm having the second thickness.

Acoustic resonator devices and filters are disclosed. An acoustic resonator includes a substrate and a piezoelectric plate supported by the substrate. A portion of the piezoelectric plate suspended across a cavity in the substrate forms a diaphragm. A decoupling dielectric layer is on a front surface of the diaphragm. An interdigital transducer (IDT) has interleaved fingers on the decoupling dielectric layer over the diaphragm. The IDT and piezoelectric plate are configured such that a radio frequency signal applied to the IDT excites shear acoustic waves in the diaphragm.

Acoustic resonator devices and filters are disclosed. An acoustic resonator includes a substrate and a piezoelectric plate supported by the substrate. A portion of the piezoelectric plate suspended across a cavity in the substrate forms a diaphragm. A decoupling dielectric layer is on a front surface of the diaphragm. An interdigital transducer (IDT) has interleaved fingers on the decoupling dielectric layer over the diaphragm. The IDT and piezoelectric plate are configured such that a radio frequency signal applied to the IDT excites shear acoustic waves in the diaphragm.

A tuning fork-type vibration piece is provided, in which a cushioning portion is formed on the base of a package and allowed to contact parts for contact of arm portions which are any parts but their edges, and the parts for contact of the arm portions that contact the cushioning portion are electrodeless regions, which prevents the risk of frequency fluctuations caused by any electrode being chipped off by contact with the cushioning portion.

A tuning fork-type vibration piece is provided, in which a cushioning portion is formed on the base of a package and allowed to contact parts for contact of arm portions which are any parts but their edges, and the parts for contact of the arm portions that contact the cushioning portion are electrodeless regions, which prevents the risk of frequency fluctuations caused by any electrode being chipped off by contact with the cushioning portion.

A crystal unit includes: a capacitor body in which a plurality of light-transmitting dielectrics and a plurality of internal electrodes are alternately stacked; a crystal piece arranged above the capacitor body and having excitation electrodes on both surfaces thereof; an external electrode formed on a surface of the capacitor body; and a first conductor portion formed in an inner layer of the capacitor body, and including one end electrically coupled to a first internal electrode among the plurality of internal electrodes, and the other end electrically coupled to the external electrode.

An RF circuit device using modified lattice, lattice, and ladder circuit topologies. The devices can include four resonator devices and four shunt resonator devices. In the ladder topology, the resonator devices are connected in series from an input port to an output port while shunt resonator devices are coupled the nodes between the resonator devices. In the lattice topology, a top and a bottom serial configurations each includes a pair of resonator devices that are coupled to differential input and output ports. A pair of shunt resonators is cross-coupled between each pair of a top serial configuration resonator and a bottom serial configuration resonator. The modified lattice topology adds baluns or inductor devices between top and bottom nodes of the top and bottom serial configurations of the lattice configuration. These topologies may be applied using single crystal or polycrystalline bulk acoustic wave (BAW) resonators.

An RF circuit device using modified lattice, lattice, and ladder circuit topologies. The devices can include four resonator devices and four shunt resonator devices. In the ladder topology, the resonator devices are connected in series from an input port to an output port while shunt resonator devices are coupled the nodes between the resonator devices. In the lattice topology, a top and a bottom serial configurations each includes a pair of resonator devices that are coupled to differential input and output ports. A pair of shunt resonators is cross-coupled between each pair of a top serial configuration resonator and a bottom serial configuration resonator. The modified lattice topology adds baluns or inductor devices between top and bottom nodes of the top and bottom serial configurations of the lattice configuration. These topologies may be applied using single crystal or polycrystalline bulk acoustic wave (BAW) resonators.