Techniques are disclosed implementing acoustic wave resonator (AWR) filter architectures to enable integrated solutions requiring significantly less passive components. The primary AWR filter topology leverages the use of parallel resonator branches, each having a relatively narrow bandwidth that may be combined to form an overall broadband filter response. This architecture may be further modified using electronically-controlled switching components to dynamically turn specific branches on or off to tune the filter, thus realizing a programmable broadband solution. Shunt resonators may also be added to the AWR filter topology, which may also be controlled with the use of electronically-controlled switching components to provide further control with respect to roll-off and the location and number of notch frequencies.

Acoustic resonators and filter devices, and method of making acoustic resonators and filter devices. An acoustic resonator includes a substrate having a surface and a piezoelectric plate having front and back surfaces, the back surface 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. An interdigital transducer (IDT) is formed on the front surface of the piezoelectric plate such that interleaved fingers of the IDT are disposed on the diaphragm. The interleaved fingers have an irregular hexagon cross-sectional shape.

Adaptive RF filters based on modulated resonators are provided. The filter architecture is based on time-interleaved commutation of passive RF resonators. The architecture can behave as a two-port filter network, with a fully tunable instantaneous filter bandwidth. The filters are applicable as miniaturized, environment-aware RF signal processing components and can be used in mobile communications.

A composite filter device includes a connection portion connected to a common terminal, a first filter between the connection portion and a first terminal, a second filter between the connection portion and a second terminal, a first inductor that is connected in series between the second filter and the connection portion, includes a first wiring electrode wound in a predetermined direction, and is provided at an internal layer of a multilayer board, and a second inductor that is connected in series between the common terminal and the connection portion, includes a second wiring electrode wound in the predetermined direction, and is provided at an internal layer of the multilayer board. The first and second wiring electrodes at least partially overlap when the multilayer board is viewed in plan.

A resonator element for use in a filter is provided. The resonator element includes a first resonator acoustically coupled to a second or third resonator or both. The first resonator has terminals for incorporation in a filter structure. A tuning circuit is coupled to the second or third resonator or both to enable tuning of the resonator element. The tuning circuit includes a variable capacitor and an inductor.

A multiplexer includes: a first bandpass filter having a first end coupled to a common terminal and a second end coupled to a first terminal, the first bandpass filter having a first passband; a second bandpass filter having a first end coupled to the common terminal and a second end coupled to a second terminal, the second bandpass filter having a second passband that does not overlap with the first passband and is higher than the first passband; and a first band-stop filter having a first end coupled to the first terminal and a second end coupled to the second terminal, the first band-stop filter having a first stopband formed of a first attenuation pole and a second attenuation pole, the first attenuation pole being located within the first passband or near the first passband, the second attenuation pole being located within the second passband or near the second passband.

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.

In accordance with an embodiment, an RF system includes a transmit path having a transmit RF filter and an adjustable transmit phase shifter/matching network coupled between the transmit RF filter and a transmit antenna port, where the adjustable transmit phase shifter/matching network is configured to transform an impedance of the transmit RF filter at a receive frequency from a first lower impedance to a first higher impedance at the transmit antenna port; and a receive path having a receive RF filter and an adjustable receive phase shifter/matching network coupled between the receive RF filter and a receive antenna port, where the adjustable receive phase shifter/matching network is configured to transform an impedance of the receive RF filter at a transmit frequency from a second lower impedance to a second higher impedance at the receive antenna port.

A notch filter includes an inductor coupled between an input node and an output node, and a dual-resonator structure coupled between the input node, the output node, and ground.

A bandpass filter includes a capacitor coupled between an input node and an output node, and a dual-resonator structure coupled between the input node, the output node, and ground.