Abstract: Apparatus and methods for true power detection are provided herein. In certain embodiments, a power amplifier system includes an antenna, a directional coupler, and a power amplifier electrically connected to the antenna by way of a through line of the directional coupler. The power amplifier system further includes a combiner that combines a first coupled signal from a first end of the directional coupler's coupled line with a second coupled signal from a second end of the directional coupler's coupled line.

Abstract: Apparatus and methods for envelope alignment calibration in radio frequency (RF) systems are provided. In certain embodiments, calibration is performed by providing an envelope signal with a peak along an envelope path, and by providing an RF signal with a first peak and a second peak to a power amplifier along an RF signal path. Additionally, an output of the power amplifier is observed to generate an observation signal using an observation receiver. The observation signal includes a first peak and a second peak corresponding to the first peak and the second peak of the RF signal, and a delay between the envelope signal and the RF signal is controlled based on relative size of the peaks of the observation signal to one another.

Abstract: An acoustic wave device with a bent section is disclosed. The acoustic wave device includes a piezoelectric layer and an interdigital transducer electrode on the piezoelectric layer. The bent section is arranged to create a curvature in a waveguide of the acoustic wave device to suppress a transverse spurious mode of the acoustic wave device.

Abstract: Disclosed herein are embodiments of an enhanced resonant frequency hexagonal ferrite material and methods of manufacturing. The hexagonal ferrite material can be Y-phase strontium hexagonal ferrite material. In some embodiments, strontium can be substituted out for a trivalent or tetravalent ion composition including potassium, thereby providing for advantageous properties.

Abstract: Aspects of this disclosure relate to an acoustic wave device that includes a bulk acoustic wave resonator and a Lamb wave element implemented on a common substrate. In some instances, the bulk acoustic wave resonator can be a film bulk acoustic wave resonator. Related radio frequency modules and wireless communication devices are disclosed.

Abstract: Apparatus and methods related to multipath bandpass filters with passband notches are provided herein. In certain configurations, a multipath bandpass filter includes multiple filter circuit branches or paths that are electrically connected in parallel with one another between an input terminal and an output terminal. The input terminal receives an input signal, and each filter circuit branch includes a downconverter that downconverts the input signal to generate a downconverted signal, a filter network that generates a filtered signal by filtering the downconverted signal, and an upconverter that upconverts the filtered signal to generate a branch output signal. The filter network includes at least one low pass filter and at least one notch filter to provide a passband with in-band notches. The branch output signals from the filter circuit branches are combined to generate an output signal at the output terminal.

Abstract: A film bulk acoustic wave resonator includes a piezoelectric film disposed over a cavity. The cavity is shaped as partial ellipse including first, second, and third vertices. The film bulk acoustic wave resonator further includes three release ports in positions that minimize etch time to remove all sacrificial material from within the cavity.

Abstract: Methods of making packaged surface acoustic wave devices are provided. The method may include forming a photosensitive resin coat over a cavity-defining structure encapsulating a surface acoustic wave device. The photosensitive resin coat may be formed using a spin-coating process, and then patterned to form a desired shape. Portions of the photosensitive resin may be removed from areas near the edge of the die, to facilitate separation of a wafer into individual dies. The method may also include forming a conductive structure using a plating process, where the conductive structure is located between the resin coat and the cavity defining structure. The photosensitive resin can include a phenol resin. The packaged surface acoustic wave devices made using a photosensitive resin coat may be relatively thin, and may have a height of less than 220 micrometers.

Abstract: A radio-frequency module includes a pole node, a throw node connected to the pole node via a radio-frequency signal path, the radio-frequency signal path including first, second, third and fourth field-effect transistors connected in series, each of the first, second, third and fourth field-effect transistors having a gate, a first coupling path coupling the gate of the first field-effect transistor to the gate of the second field-effect transistor, a second coupling path coupling the gate of the third field-effect transistor to the gate of the fourth field-effect transistor, and a third coupling path coupling the first coupling path to the second coupling path.

Abstract: A power amplifier module can include one or more switches, a coupler module, input signal pins, and a controller having first and second output terminals. The input signal pins can receive a voltage input/output signal, a clock input signal, and a data input signal. The controller can (i) set a mode of the one or more switches using a synchronous communication protocol in which the controller outputs a synchronous clock signal on the first output terminal and a data signal on the second output terminal, when the power amplifier module is in a first operating mode, or (ii) set a mode of the coupler module using an asynchronous communication protocol in which the controller outputs a first asynchronous control signal on the first output terminal and a second asynchronous control signal on the second output terminal, when the power amplifier module is in a second operating mode.

Abstract: Reconfigurable antenna systems integrated with a metal case are provided herein. In certain embodiments, user equipment (UE) for a cellular network includes a metal case and an antenna system for transmitting and/or receiving wireless signals. The antenna system includes an antenna element and a tuning conductor that is spaced apart from the antenna element and operable to load the antenna element. At least one of the antenna element or the tuning conductor is formed in the metal case. For example, a plasma process can be used to create transparent electromagnetic windows at a given frequency while shielding underlying components from spurious signals at other frequencies. Such plasma shielding processes can be used to turn conductive regions of the metal case into non-conductive metal oxide, thereby providing a mechanism for electrical isolation between various regions of the metal case.

Abstract: Front end systems with switched termination for enhanced intermodulation distortion performance are provided herein. The switched termination can be used on transmit paths and/or receive paths of the front end system to suppress impedance variation when the signal paths are inactive. For example, with respect to switched termination for transmit paths, a front end system can include a frequency multiplexing circuit connected to a band switch by a first radio frequency (RF) signal path and by a second RF signal path. The band switch selectively provides the frequency multiplexing circuit with a first transmit signal over the first RF signal path and with a second transmit signal over the second RF signal path. The front end system further includes a switched termination circuit in shunt with the first RF signal path and operable to turn on to suppress impedance variation when the first RF signal path is inactive.

Abstract: A front end module having transmit loopback functionality may be operated by conducting a loopback signal from an output of a power amplifier to a receive port on a transmit loopback path and conducting a radio frequency receive signal from an antenna port to the receive port on a receive path. The transmit loopback path includes a first switch coupled between the output of the power amplifier and the receive port. The receive path includes a second switch coupled between the antenna port, where the receive port and is without the first switch.

Abstract: Methods for operating amplifiers and related devices. In some embodiments, a method for amplifying a signal can include partially amplifying a signal with a common amplification stage. The method can further include providing a bias signal to a selected one of a plurality of dedicated amplification stages each coupled to the common amplification stage and including an output node, such that the selected dedicated amplification stage further amplifies the partially amplified signal and provides the further amplified signal at the respective output node.

Abstract: A multiplexing system can include a first diplexer and a second diplexer. The first diplexer can have a first transmit terminal, a first receive terminal, and a first common terminal. The first diplexer can be configured to filter a first transmit signal to a first cellular frequency band and output the filtered first transmit signal. The first diplexer can be further configured to filter a first receive signal to a second cellular frequency band and output the filtered first receive signal. The second diplexer can have a second transmit terminal, a second receive terminal, and a second common terminal. The second diplexer can be configured to filter a second transmit signal to the second cellular frequency band and output the filtered second transmit signal. The second diplexer can be further configured to filter a second receive signal to the first cellular frequency band and output the filtered second receive signal.

Abstract: Voltage supply system with boost converter and charge pump. A voltage supply system can include a boost converter controllable to receive an input voltage at an input node and generate an output voltage when the output voltage is greater than or equal to the input voltage. The voltage supply system can include a charge pump controllable to receive the input voltage at the input node and generate the output voltage when the output voltage is less than the input voltage. The voltage supply system can further include a controller configured to receive a control signal and control the boost converter or the charge pump to generate the output voltage at an output node based on the control signal.

Abstract: According to certain aspects, a method for manufacturing packaged radio-frequency (RF) devices can include: providing a packaging substrate configured to receive a plurality of components, the packaging substrate including a first side and a second side; mounting a first circuit on the first side of the packaging substrate; implementing a first overmold structure on the first side of the packaging substrate, the first overmold structure substantially encapsulating the first component; mounting a second component on the second side of the packaging substrate, the second component being located in an area of the second side where redundant ground pins may be located; implementing a set of through-mold connections on the second side of the packaging substrate, the set of through-mold connections including signal pins and ground pins; forming a second overmold structure over the component and the set of through-mold connections; and removing a portion of the second overmold structure.

Abstract: A front-end module comprises a bias network including a current mirror, a junction temperature sensor, an n-bit analog-to-digital converter, an n-bit current source bank configured to automatically set reference current levels for one or more operating temperature regions, and a power amplifier. The bias network, junction temperature sensor, n-bit analog-to-digital converter, n-bit current source bank, and power amplifier are integrated on a first semiconductor die.

Abstract: An acoustic wave device includes a layered substrate having a piezoelectric material layer bonded to a second material layer including a material having a higher thermal conductivity than the piezoelectric material layer, interdigital transducer electrodes disposed on a surface of the piezoelectric material layer, contact pads disposed on the piezoelectric material layer and in electrical contact with the interdigital transducer electrodes, external bond pads disposed on the second material layer, and conductive vias passing through the layered substrate and providing electrical contact between the contact pads and external bond pads.

Abstract: A temperature compensation circuit comprises a temperature coefficient circuit that generates a temperature coefficient that is temperature dependent and a compensation circuit that generates a compensation signal based on an indication of temperature of an amplifier and the temperature coefficient, and based on the compensation signal, a gain of the amplifier is adjusted to improve amplifier linearity during data bursts.