Abstract: Aspects of this disclosure relate to a tunable filter with harmonic rejection. The tunable filter includes mutually coupled inductors and a tunable capacitance circuit electrically connected to at least one of the mutually coupled inductors. The tunable capacitance circuit includes N switches configured to adjust effective capacitance of the tunable capacitance circuit to tune harmonic rejection of the tunable filter for at least 2×2N harmonics. The tunable filter can filter a radio frequency signal. Related methods, radio frequency systems, radio frequency modules, and wireless communication devices are also disclosed.

Abstract: Aspects of this disclosure relate to a surface acoustic wave filter with an acoustic velocity adjustment structure. The surface acoustic wave filter can include a first interdigital transducer electrode disposed on a piezoelectric layer, an acoustic reflector disposed on the piezoelectric layer, and a second interdigital transducer electrode disposed on the piezoelectric layer. The second interdigital transducer electrode is longitudinally coupled to the first interdigital transducer electrode and positioned between the first interdigital transducer electrode and the acoustic reflector. The acoustic velocity adjustment structure can be positioned over at least a gap between the first interdigital transducer electrode and the second interdigital transducer electrode.

Abstract: A switched attenuator comprising a radio frequency input, a radio frequency output and an attenuation cell connected between the RF input and the RF output. The attenuation cell includes a variable switch with a variable on-resistance (Ron).

Abstract: Methods related to radio-frequency (RF) switching devices having improved voltage handling capability. In some embodiments, a method for fabricating an RF switching device can include: providing a semiconductor substrate; forming a plurality of field-effect transistors (FETs) on the semiconductor substrate such that the FETs have a non-uniform distribution of a parameter; and connecting the FETs to form a stack, such that the non-uniform distribution results in the stack having a first voltage handling capacity that is greater than a second voltage handling capacity corresponding to a similar stack having a substantially uniform distribution of the parameter.

Abstract: The disclosed technology generally relates dielectric materials, and more particularly to a combination of co-fireable dielectric materials that can be attached to each other without the use of adhesives. In an aspect, a composite article comprises a magnetic portion comprising a nickel zinc ferrite. The composite article additionally comprises a non-magnetic portion contacting the magnetic portion, the non-magnetic portion comprising a spinel-structured oxide comprising Mg2-xAl2xTi1-xO4 and having a dielectric constant between about 7 and 14, wherein 0<x?1.

Abstract: A packaged radio-frequency device can include a packaging substrate configured to receive one or more components, the packaging substrate including a first side and a second side. The packaging substrate may include a first component mounted on the first side and a first overmold structure implemented on the first side, the first overmold structure substantially encapsulating the first component. The packaging substrate may further include a set of through-mold connections implemented on the second side of the packaging substrate, the set of through-mold connections including signal pins and ground pins, a second component mounted on the second side of the packaging substrate, the second component being located in an area of the second side configured to implement a redundant ground pad or a redundant portion of a ground pad, and a second overmold structure substantially encapsulating one or more of the second component or the set of through-mold connections.

Abstract: Laser-marked packaged surface acoustic wave devices are provided. The laser-marked packaged surface acoustic wave device may include a package structure encapsulating a surface acoustic wave device on a first side of a piezoelectric substrate. The opposite side of the piezoelectric substrate can be directly marked using a laser. The laser may be a deep ultraviolet laser. By directly marking the piezoelectric substrate itself, the use of a separate marking film can be avoided, making the packaged surface acoustic wave device thinner. When the laser has a wavelength readily absorbed by the piezoelectric substrate, a relatively shallow marking may be made in the piezoelectric substrate. The markings can extend less than 1 micrometer into the piezoelectric substrate, so as not to affect the structural integrity of the piezoelectric substrate or the operation of the packaged surface acoustic wave device.

Abstract: Systems and methods including variable power amplifier bias impedance are disclosed. In one aspect, there is provided a power amplifier system including a bias circuit configured to receive a bias voltage and generate a bias signal and a power amplifier stage configured to receive an input radio frequency (RF) signal and generate an output RF signal. The power amplifier system may also include a bias impedance component operatively coupled between the bias circuit and the power amplifier stage. The bias impedance is component configured to receive a control signal and adjust an impedance value of the bias impedance component in response to the control signal.

Abstract: Aspects of this disclosure relate to an acoustic wave device that includes high velocity layers on opposing sides of a piezoelectric layer. A temperature compensation layer can be positioned between one of the high velocity layers and the piezoelectric layer. The acoustic wave device can be arranged to generate a boundary acoustic wave having a higher velocity than a respective acoustic velocity of each of the high velocity layers.

Abstract: A multi-layer piezoelectric substrate silicon package comprises a bottom filter including a cap wafer of the bottom filter, and a device wafer of the bottom filter, the cap wafer of the bottom filter and the device wafer of the bottom filter each having a first through silicon via configured to provide an electrical path from a first bottom terminal of the device wafer of the bottom filter to a first top terminal of the cap wafer of the bottom filter.

Abstract: In some embodiments, a radio-frequency device can be manufactured by a method that includes forming or providing a substrate, fabricating or providing a flip chip die having a front side and a back side, and including an integrated circuit implemented on the front side, and mounting the front side of the flip chip die on the substrate. The method can further include implementing a shielding component over the back side of the flip chip die to provide electromagnetic shielding between a first region within or on the flip chip die and a second region away from the flip chip die.

Abstract: A clock product includes a time-to-digital converter responsive to an input clock signal, a reference clock signal, and a time-to-digital converter calibration signal. The time-to-digital converter includes a coarse time-to-digital converter and a fine time-to digital converter. The clock product includes a calibration circuit including a phase-locked loop. The calibration circuit is configured to generate the time-to-digital converter calibration signal. The clock product includes a controller configured to execute instructions that cause the phase-locked loop to generate an error signal for each possible value of a fine time code of a digital time code generated by the time-to-digital converter and to average the error signal over multiple clock cycles to generate an average error signal.

Abstract: Amplifier having input power protection. In some embodiments, an amplifier circuit can include an input node and an output node, and an amplifier implemented between the input node and the output node. The amplifier circuit can further include a bias circuit configured to provide a bias signal to the amplifier. The amplifier circuit can further include a protection circuit configured to generate a detected voltage representative of a peak of a radio-frequency signal present at the input node. The protection circuit can be further configured to enable a protection mode when the detected voltage is greater than a first threshold value and to disable the protection mode when the detected voltage is less than a second threshold value that is less than the first threshold value.

Abstract: An isolated gate driver includes a first input terminal to receive gate information and one or more input terminals to receive configuration information. A modulation circuit generates a modulated signal having four possible states, each of the four possible states corresponding to a different unique pair of values of the gate information and the configuration information. The modulation circuit represents two of the states using on-off keying (OOK) while the configuration information is at a first value and represents two of the states as a modification to the OOK modulation based on the configuration information being at a second value. The modulated signal is sent over an isolation communication channel coupling a transmitter and receiver of the isolated gate driver.

Abstract: Systems and methods for duplexer circuits having signal leakage cancellation are provided. In one aspect, a duplexer circuit includes a transmit path splitter configured to split a radio frequency transmit signal into a pair of radio frequency transmit signals, and a receive path splitter configured to combine a pair of radio frequency receive signals. The duplexer circuit also includes an antenna path splitter configured to combine a pair of radio frequency transmit signals and split a radio frequency receive signal into the pair of radio frequency receive signals, and first and second duplexers. The first duplexer is coupled to a first leg of each of the transmit path splitter, the receive path splitter, and the antenna path splitter, and the second duplexer is coupled to a second leg of each of the transmit path splitter, the receive path splitter, and the antenna path splitter.

Abstract: An acoustic wave device comprises a piezoelectric substrate, interdigital transducer electrodes having an electrode pitch ?0, and first and second reflector gratings disposed on opposite respective sides of the interdigital transducer electrodes in a propagation direction of a main acoustic wave through the acoustic wave device, the first reflector grating having a different electrode pitch ?1 than an electrode pitch ?2 of the second reflector grating to suppress ripples in a conductance curve of the acoustic wave device.

Abstract: Aspects of this disclosure relate to a surface acoustic wave device with a vertical stack over a piezoelectric layer. The vertical stack can include a first acoustic reflector disposed on the piezoelectric layer, a second acoustic reflector disposed on the piezoelectric layer, and an interdigital transducer electrode disposed on the piezoelectric layer and positioned between the first acoustic reflector and the second acoustic reflector. The interdigital transducer electrode has a first side that is closer to the first acoustic reflector and a second side that is closer to the second acoustic reflector. A vertical arrangement of the vertical stack can be configured such that an acoustic wave propagation velocity of a first region between the first side and a first reflector is faster than an acoustic wave propagation velocity of a second region between the first side and the second side.

Abstract: Envelope tracking schemes for Doherty power amplifiers are provided herein. In certain embodiments, an envelope tracking system includes a carrier amplifier that amplifies a first radio frequency signal, a peaking amplifier that amplifies a second radio frequency signal corresponding to a delayed version of the first radio frequency signal, an envelope tracker that generates a first power supply voltage that powers the carrier amplifier, and a delay circuit that delays the first power supply voltage to generate a second power supply voltage that powers the peaking amplifier. The envelope tracker controls a voltage level of the first power supply voltage to track an envelope of the first radio frequency signal. Thus, supply modulation is used to achieve gains in linearity, efficiency, and/or other performance metrics.

Abstract: An acoustic wave device is disclosed. The acoustic wave device includes a support layer, a ceramic layer positioned over the support layer, a piezoelectric layer positioned over the ceramic layer, and an interdigital transducer electrode positioned over the piezoelectric layer. The support layer has a higher thermal conductivity than the ceramic layer. The ceramic layer can be a polycrystalline spinel layer. The acoustic wave device can be a surface acoustic wave device configured to generate a surface acoustic wave.

Abstract: Disclosed are embodiments of making a barium magnesium tantalate. The method can include providing barium magnesium tantalate and incorporating one of Ba2MgWO6, Ba8LiTa5WO24, Ba8LiTa5WO24, Ba2MgWO6, Ba3LaTa3O12, Ba8LiTa5WO24, BaLaLiWO6, Ba4Ta2WO12, Ba2La2MgW2O12, BaLaLiWO6, Sr3LaTa3O12, and SrLaTaO12 into the barium magnesium tantalate to form a solid solution having a high Q value.