Embodiments of resonator circuits and modulating resonators and are described generally herein. One or more acoustic wave resonators may be coupled in series or parallel to generate tunable filters. One or more acoustic wave resonances may be modulated by one or more capacitors or tunable capacitors. One or more acoustic wave modules may also be switchable in a filter. Other embodiments may be described and claimed.

An acoustic wave device includes a support substrate, a piezoelectric laminate, and first and second interdigital transducer electrodes. The piezoelectric laminate includes an intermediate layer provided directly or indirectly on the support substrate and a piezoelectric thin film provided on the intermediate layer. The first and second interdigital transducer electrodes are provided on the piezoelectric thin film of the piezoelectric laminate so as to be disposed in an identical or substantially identical plane. In the piezoelectric laminate, a thickness of a portion where the first interdigital transducer electrode is provided is different from a thickness of a portion where the second interdigital transducer electrode is provided.

An example resonating structure comprises a substrate, a resonator body, and an anchoring body for anchoring the resonator body to the substrate. The resonator body includes a layer of base material and, deposited on top of the layer of base material, a layer of mismatch material having a mismatch in temperature coefficient of elasticity (TCE) relative to the base material. The base material is doped with a dopant having a concentration chosen so as to minimize a second order temperature coefficient of frequency for the resonator body. The thickness of the layer of the mismatch material is chosen so as to minimize a first order temperature coefficient of frequency for the resonator body.

An acoustic filter device for telecommunication devices includes a first acoustic band pass filter having a corresponding first passband and a second acoustic band pass filter having a corresponding second passband. The second acoustic band pass filter is connected in parallel with the first acoustic band pass filter to provide a combined passband including the first and second passbands.

A radio frequency filter includes communication bandpass filters disposed corresponding respectively to a plurality of communication bands, a switch, and a matching circuit. The switch includes a common terminal and a plurality of optionally selectable terminals, the plurality of optionally selectable terminals being individually connected to the plurality of bandpass filters in a one-to-one relation. The matching circuit is connected to the common terminal and is a common matching circuit to the plurality of communication bandpass filters. The plurality of communication bandpass filters are set such that filter characteristics of a serial circuit in combination of one of the plurality of communication bandpass filters, the one being selected by the switch, and the common matching circuit are improved in comparison with filter characteristics of the selected communication bandpass filter with respect to the communication band corresponding to the selected communication bandpass filter.

A filter includes shunt circuits coupled between a reference node and each of an input port, an output port, a first node, and a second node. Resonant networks are coupled between the input port and the second node, and between the first node and the output port. Storage element circuits are coupled between the input port and the first node, and between the second node and the output port. The shunt circuits have an equivalent shunt circuit frequency response that partly defines a high passband frequency of the filter, the resonant networks have an equivalent resonant network frequency response that partly defines a low passband frequency of the filter, and the storage element circuits have an equivalent storage element circuit frequency response that defines a stopband frequency of the filter between the low passband frequency and the high passband frequency.

A surface acoustic wave filter is disclosed. The surface acoustic wave filter includes a substrate, and first and second surface acoustic wave filter structures disposed on first and second main surfaces of the substrate, respectively. The first surface acoustic wave filter structure includes a first piezoelectric layer a plurality of first surface acoustic wave resonators formed on a top surface of the first piezoelectric layer, and a first wiring layer connecting the first surface acoustic wave resonators to each other. The second surface acoustic wave filter structure includes a second piezoelectric layer, a plurality of second surface acoustic wave resonators formed on a bottom surface of the second piezoelectric layer, and a second wiring layer connecting the second surface acoustic wave resonators to each other. A plurality of through electrodes extends through the substrate, the first piezoelectric layer, and the second piezoelectric layer. A circuit including the first surface acoustic wave resonators and the first wiring layer on the top surface of the first piezoelectric layer forms at least one first radio frequency filter, and a circuit including the plurality of second surface acoustic wave resonators and the second wiring layer on the bottom surface of the second piezoelectric layer forms at least one second radio frequency filter. The at least one first radio frequency filter and the at least one second radio frequency filter belong to different frequency bands.

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.

A switch module includes a switch circuit and a filter. The switch circuit includes two or more selection terminals, a common terminal provided for the two or more selection terminals, and first and second bypass terminals. The filter is connected between the first and second bypass terminals and reduces harmonics of a radio-frequency signal which passes through the filter. The switch circuit is selectively switched between a first connection mode and a second connection mode. In the first connection mode, the common terminal is connected to any of the two or more selection terminals. In the second connection mode, the common terminal is connected to the first bypass terminal and the second bypass terminal is connected to any of the two or more selection terminals.

A filter circuit is provided which allows the pass band to be tuned to a desired communication signal while achieving increased attenuation in a given frequency band that lies outside the pass band. A filter circuit includes a fixed filter and a tunable filter. The fixed filter has a pass band wider than a frequency band corresponding to a predetermined communication signal and overlapping with the frequency band corresponding to the communication signal. The tunable filter has a stop band narrower than the pass band of the fixed filter and having tunable frequency. The fixed filter and the tunable filter are connected in series.