Abstract: Filter devices. A first chip includes a first base, a first piezoelectric membrane having a first thickness, and a first acoustic Bragg reflector sandwiched between the first piezoelectric membrane and the first base. A first interdigital transducer (IDT) of a first solidly-mounted membrane resonator is formed on a surface of the first piezoelectric membrane. A second chip includes a second base, a second piezoelectric membrane having a second thickness less than the first thickness, and a second acoustic Bragg reflector sandwiched between the second piezoelectric membrane and the second base. A second IDT of a second solidly-mounted membrane resonator is formed on a surface of the second piezoelectric membrane. A circuit card is coupled to the first chip and the second chip, the circuit card including at least one conductor for making an electrical connection between the first IDT and the second IDT.

Abstract: Filter devices. A first chip includes a first base, a first piezoelectric membrane having a first thickness, and a first acoustic Bragg reflector sandwiched between the first piezoelectric membrane and the first base. A first interdigital transducer (IDT) of a first solidly-mounted membrane resonator is formed on a surface of the first piezoelectric membrane. A second chip includes a second base, a second piezoelectric membrane having a second thickness less than the first thickness, and a second acoustic Bragg reflector sandwiched between the second piezoelectric membrane and the second base. A second IDT of a second solidly-mounted membrane resonator is formed on a surface of the second piezoelectric membrane. A circuit card is coupled to the first chip and the second chip, the circuit card including at least one conductor for making an electrical connection between the first IDT and the second IDT.

Abstract: Filter devices are disclosed. A filter device includes a piezoelectric plate comprising a supported portion, a first diaphragm, and a second diaphragm. The supported portion is attached to a substrate and the first and second diaphragms spans respective cavities in the substrate. A first interdigital transducer (IDT) has interleaved fingers on the first diaphragm. A second interdigital transducer (IDT) has interleaved fingers on the second diaphragm. A first dielectric layer is between the interleaved fingers of the first IDT, and a second dielectric layer is between the interleaved fingers of the second IDT. A thickness of the first dielectric layer is greater than a thickness of the second dielectric layer. The piezoelectric plate and the first and second IDTs are configured such that radio frequency signals applied to first and second IDTs excite primary shear acoustic modes in the respective diaphragms.

Abstract: Networks and filters are disclosed. A network includes a resonator that exhibits both a resonance and an anti-resonance and an inverter circuit connected in parallel with the resonator to form a composite resonator. An anti-resonant frequency of the composite resonator is different from the resonator's anti-resonant frequency.

Abstract: Filter devices. A first chip includes a first interdigital transducer (IDT) of a first acoustic resonator formed on a surface of a first piezoelectric wafer having a first thickness, interleaved fingers of the first IDT disposed on a portion of the first piezoelectric wafer spanning a first cavity in a first base. A second chip includes a second IDT of a second acoustic resonator formed on a surface of a second piezoelectric wafer having a second thickness less than the first thickness, interleaved fingers of the second IDT disposed on a portion of the second piezoelectric wafer spanning a second cavity in a second base. A circuit card coupled to the first chip and the second chip includes at least one conductor for making an electrical connection between the first IDT and the second IDT.

Abstract: Filter devices. A first chip includes a first interdigital transducer (IDT) of a first acoustic resonator formed on a surface of a first piezoelectric wafer having a first thickness, interleaved fingers of the first IDT disposed on a portion of the first piezoelectric wafer spanning a first cavity in a first base. A second chip includes a second IDT of a second acoustic resonator formed on a surface of a second piezoelectric wafer having a second thickness less than the first thickness, interleaved fingers of the second IDT disposed on a portion of the second piezoelectric wafer spanning a second cavity in a second base. A circuit card coupled to the first chip and the second chip includes at least one conductor for making an electrical connection between the first IDT and the second IDT.

Abstract: Networks and filters are disclosed. A network includes a resonator that exhibits both a resonance and an anti-resonance and an inverter circuit connected in parallel with the resonator to form a composite resonator. An anti-resonant frequency of the composite resonator is different from the resonator's anti-resonant frequency.

Abstract: Resonator devices and filter devices are disclosed. An acoustic resonator includes a substrate and a piezoelectric plate having front and back surfaces separated by a piezoelectric plate thickness greater than or equal to 50 nm and less than or equal to 200 nm. An acoustic Bragg reflector is between the substrate and the back surface of the piezoelectric plate. A conductor pattern including an interdigital transducer (IDT) is on the front surface of the piezoelectric plate.

Abstract: Filter devices. A first chip includes a first base, a first piezoelectric membrane having a first thickness, and a first acoustic Bragg reflector sandwiched between the first piezoelectric membrane and the first base. A first interdigital transducer (IDT) of a first solidly-mounted membrane resonator is formed on a surface of the first piezoelectric membrane. A second chip includes a second base, a second piezoelectric membrane having a second thickness less than the first thickness, and a second acoustic Bragg reflector sandwiched between the second piezoelectric membrane and the second base. A second IDT of a second solidly-mounted membrane resonator is formed on a surface of the second piezoelectric membrane. A circuit card is coupled to the first chip and the second chip, the circuit card including at least one conductor for making an electrical connection between the first IDT and the second IDT.

Abstract: Filter devices. A first chip includes a first interdigital transducer (IDT) of a first acoustic resonator formed on a surface of a first piezoelectric wafer having a first thickness, interleaved fingers of the first IDT disposed on a portion of the first piezoelectric wafer spanning a first cavity in a first base. A second chip includes a second IDT of a second acoustic resonator formed on a surface of a second piezoelectric wafer having a second thickness less than the first thickness, interleaved fingers of the second IDT disposed on a portion of the second piezoelectric wafer spanning a second cavity in a second base. A circuit card coupled to the first chip and the second chip includes at least one conductor for making an electrical connection between the first IDT and the second IDT.

Abstract: Filter devices and methods of fabricating filter devices. A filter device includes a first chip and a second chip. The first chip has a first material stack and contains one or more series resonators of a ladder filter circuit. The second chip has a second material stack and contains one or more shunt resonators of the ladder filter circuit. The first material stack and the second material stack are different.

Abstract: Filter devices and methods of fabricating filter devices. A filter device includes a first chip and a second chip. The first chip has a first material stack and contains one or more series resonators of a ladder filter circuit. The second chip has a second material stack and contains one or more shunt resonators of the ladder filter circuit. The first material stack and the second material stack are different.

Abstract: Networks and filters are disclosed. A network includes a resonator that exhibits both a resonance and an anti-resonance and an inverter circuit connected in parallel with the resonator to form a composite resonator. An anti-resonant frequency of the composite resonator is different from the resonator's anti-resonant frequency.

Abstract: An acoustic filter comprises a piezoelectric layer; an acoustic resonator structure monolithically disposed on the piezoelectric layer, the acoustic resonator structure including an arrangement of planar interdigitated resonator fingers; and a lumped capacitive structure monolithically disposed on the piezoelectric layer and being electrically coupled to the acoustic resonator structure, the lumped capacitive structure including an arrangement of planar interdigitated capacitive fingers, each of at least one of the interdigitated capacitive fingers having an edge that is entirely continuous.

Abstract: Bandpass filters and methods of designing bandpass filters are disclosed. A bandpass filter includes a plurality of series acoustic resonators connected in series between an input and an output, and a plurality of\ shunt acoustic resonators, each shunt acoustic resonator connected between a ground and one of the input, the output, and a junction between two of the plurality of series acoustic resonators. A first shunt resonator of the plurality of shunt resonators has a motional resonance frequency higher than and adjacent to an upper edge of a passband of the bandpass filter.

Abstract: Multi-band filters, communications devices, and methods of designing multi-band filters are disclosed. A multi-band filter has a lower pass-band and an upper pass-band separated by an intervening stop-band. The multi-band filter includes a first ladder network and a second ladder network coupled in series. The first ladder network provides transmission zeros at frequencies below a lower edge of the lower pass-band and transmission zeros at frequencies above an upper edge of the upper pass-band. The second ladder network provides transmission zeros at frequencies within the intervening stop-band.

Abstract: Communications devices, triplexers, high-pass filters, and low-pass filters are disclosed. A communications device includes a triplexer having a common port and first, second, and third branch ports. A hybrid LC/SAW high-pass filter is connected between the common port and the third branch port, a hybrid LC/SAW low-pass filter is connected between the common port and an internal node, an LC high-pass filter is connected between the internal node and the second branch port, and an LC low-pass filter is connected between the internal node and the first branch port.

Abstract: Multi-band filters, communications devices, and methods of designing multi-band filters are disclosed. A multi-band filter has a lower pass-band and an upper pass-band separated by an intervening stop-band. The multi-band filter includes a first ladder network and a second ladder network coupled in series. The first ladder network provides transmission zeros at frequencies below a lower edge of the lower pass-band and transmission zeros at frequencies above an upper edge of the upper pass-band. The second ladder network provides transmission zeros at frequencies within the intervening stop-band.

Abstract: There are disclosed radio frequency multiplexers and methods of designing radio frequency multiplexers. A radio frequency multiplexer includes three or more band-pass filters having respective passbands, each band-pass filter comprising two or more acoustic resonators. A first end of each of the three or more band-pass filters is connected to a respective branch port. A second end of each of the three or more band-pass filters is connected to a common node without an intervening phasing network. A shunt reactive element connected between the common node and ground.

Abstract: Bandpass filters and methods of designing bandpass filters are disclosed. A bandpass filter includes a plurality of series acoustic resonators connected in series between an input and an output, and a plurality of\ shunt acoustic resonators, each shunt acoustic resonator connected between a ground and one of the input, the output, and a junction between two of the plurality of series acoustic resonators. A first shunt resonator of the plurality of shunt resonators has a motional resonance frequency higher than and adjacent to an upper edge of a passband of the bandpass filter.