The present disclosure provides a bulk acoustic wave resonance device, a bulk acoustic wave filter device and a radio frequency front end device. The bulk acoustic wave resonance device includes a first layer including a cavity disposed at a first side of the first layer; a first electrode layer disposed in the cavity; a second layer disposed at the first side and disposed on the first electrode layer, and the second layer is a flat layer and covers the first cavity; and a second electrode layer disposed at the first side and disposed on the second layer, and the first electrode layer includes at least two first electrode bars or the second electrode layer includes at least two second electrode bars. The present disclosure can increase the difference between acoustic impedance of a resonance region and a non-resonance region, thereby increasing Q value of the resonance device.

A multi-frequency low noise amplifier includes an input matching network, an amplifying circuit and an output matching network. The input matching network includes a first out-of-band rejection circuit and a first frequency band selection circuit. The output matching network includes a second out-of-band rejection circuit and a second frequency band selection circuit. The first out-of-band rejection circuit can reject signal of any frequency band in the radio frequency signals so that signals of the remaining frequency bands can pass through. The first frequency band selection circuit can screen out the signals of reference frequency spots from the remaining frequency bands. The second frequency band selection circuit can screen out the signals of partial frequency spots from the amplified signals of reference frequency spots. The second out-of-band rejection circuit can reject the signal of any frequency spot in the signals of partial frequency spots.

A differential tuned inductor and a multilayer tunable transformer for an integrated circuit device for microwave and RF applications are disclosed. The tunable inductor can be used in differential artificial delay lines to achieve delay tuning while preserving impedance matching. The tunable transformer can also be used for mixer drives to achieve wider operational performance.

An RF transceiver front end includes a receiver limb including a length of transmission line, an impedance matching network, a downstream shunt switch and a downstream further receiver component and a transmitter limb. The impedance matching network is configured to transform the input impedance of the further receiver component to match the input impedance of the receiver limb when the shunt switch is open and the RF transceiver front end is operable in receiver mode. The impedance matching network is further configured to transform the input impedance of the shunt switch to present an open circuit as the input impedance of the receiver limb when the shunt switch is closed and the RF transceiver front end is operable in transmitter mode. The length of transmission line can be from zero to less than λ/4 at the operating frequency of the RF transceiver.

An acoustic wave device includes a silicon support substrate that includes first and second main surfaces opposing each other, a piezoelectric structure provided on the first main surface and including the piezoelectric layer, an IDT electrode provided on the piezoelectric layer, a support layer provided on the first main surface of the silicon support substrate and surrounding the piezoelectric layer, a cover layer provided on the support layer, a through-via electrode that extending through the silicon support substrate and the piezoelectric structure, and a first wiring electrode connected to the through-via electrode and electrically connected to the IDT electrode. The piezoelectric structure includes at least one layer having an insulating property, the at least one layer including the piezoelectric layer. The first wiring electrode is provided on the layer having an insulating property in the piezoelectric structure.

Methods and devices used in mobile receiver front end to support multiple paths and multiple frequency bands are described. The presented devices and methods provide benefits of scalability, frequency band agility, as well as size reduction by using one low noise amplifier per simultaneous outputs. Based on the disclosed teachings, variable gain amplification of multiband signals is also presented.

Power supplies for electronic devices (e.g. medical imaging devices) are disclosed herein. In one embodiment, a switched mode power supply is minimized in size and weight while maintaining efficiency and an artifact-free image using power supply design techniques tailored to increasing the power conversion frequency to be above the desired receive band of an ultrasound imaging system. In another embodiment, a switched mode power supply is minimized in size and weight while maintaining efficiency and an artifact-free image using power supply design techniques tailored to increasing the power conversion frequency to be just below the desired receive band of an ultrasound imaging system causing the third harmonic and possibly the second harmonic to fall just above the desired receive band.

Methods and devices for reducing DC current consumption of a multi-stage LNA amplifier. According to one aspect, first and second amplification stages are stacked to provide a common conduction path of a DC current. The first stage includes a common-source amplifier, the second stage includes a common-drain amplifier. Coupling between the two stages is provided by series connection of load inductors of the respective stages and a capacitor coupled at a common node between the inductors. According to another aspect, a current splitter circuit is used to split a current to the first stage according to two separate conduction paths, one common path to the two stages, and another separate from the second stage. According to yet another aspect, the current splitter circuit includes a feedback loop that controls the splitting of the current so to maintain a constant current through the common path.

A power amplifier may be configured to operate in an on state and an off state. The power amplifier may include a plurality of transistors and an impedance controller circuit. The plurality of transistors may be electrically coupled to an electrical ground and an output of the power amplifier. The impedance controller circuit may be electrically coupled to the plurality of transistors and a reference voltage. The impedance controller circuit may be configured to provide the reference voltage to the plurality of transistors when the power amplifier is in the off state to cause a leakage current to flow between the reference voltage and the electrical ground.

An apparatus includes a transformer including a first inductor, a second inductor, and a third inductor. The apparatus also includes a power amplifier having an output coupled to the first inductor, a low-noise amplifier having an input coupled to a first terminal of the third inductor, and a fourth inductor having a first terminal and a second terminal, wherein the second terminal of the fourth inductor is coupled to a second terminal of the third inductor. The apparatus also includes a switch coupled between the first terminal of the third inductor and the first terminal of the fourth inductor.