A power amplifier impedance adjustment circuit is disclosed. In one aspect, the impedance adjustment circuit includes an input node configured to receive a radio frequency (RF) signal from a power amplifier, an output node configured to provide the RF signal to an antenna switch die, a plurality of electrical components arranged between the input node and the output node, and at least one switch configured to selectively electrically connect at least one of the electrical components to the input node and the output node. For each state of the at least one switch, the impedance adjustment circuit is configured to adjust an impedance of the power amplifier from a natural tune point in a direction towards a target tuned impedance point when viewed on a Smith chart.

A radio-frequency module includes a first terminal configured to receive a signal from an antenna, a substrate, a first filter element on the substrate, a first switch including a first switch terminal and a second switch terminal connectable to the first switch terminal, and connected between the first terminal and the first filter element, and a second switch including a third switch terminal. The first filter element is connected between the second switch terminal and the third switch terminal, the first switch and the second switch are included in a semiconductor chip, and the semiconductor chip is on the substrate.

An integrated isolator circuit for isolating receiver and transmitter in a Time-Division Duplex transceiver is disclosed. The integrated isolator circuit comprises a first node, a second node and. a third node. The integrated isolator circuit further comprises a first capacitor connected in series with a first switch and connected between the first and second nodes. The integrated isolator circuit further comprises a first inductor connected between the first and second nodes and a second capacitor connected between the second node and the third node. The first switch has an on state and an off state, and the integrated isolator circuit is configured to have a different impedance at a certain operating frequency by controlling the state of the first switch.

Disclosed is an impedance matcher for use in a communication system, operable to match a transmitter or receiver, respectively, to an associated antenna, comprising a stub matching circuit and a phase shifter, whereby, in use, energy flows from a source to the phase shifter, to the stub matching circuit and to a load.

A multiplexer (10) includes a common terminal (100c), a filter (21) that supports Band 41, a filter (22) that supports Band 40, and a filter (23) that supports Band 1Rx. A matching circuit (11) includes a capacitor (C1) connected in a path (111), a switch (SW1) connected between a ground and a node in the path (111) between the capacitor (C1) and the filter (21), a resonant circuit connected in a path (112) and having a resonant frequency in Band 40, the resonant frequency being a frequency at which an impedance is minimum, a switch (SW2) connected between the ground and a node in the path (112) between the resonant circuit and the filter (22), an inductor (L1) connected in a path (113), and a switch (SW3) connected between the ground and a node in the path (113) between the inductor (L1) and the filter (23).

A radio-frequency impedance tuner can include first and second nodes, a bypass path, first and second series capacitance paths, and an inductance path, with each path being implemented between the first and second nodes and including a switch configured to allow the path to couple or uncouple the first and second nodes. The tuner can further include first and second shunt paths, with each shunt path being implemented between the second node and ground and including a switch configured to allow the shunt path to couple or uncouple the second node and the ground. The tuner can further include a switchable grounding path implemented along the inductance path and configured to allow the inductance path to function as a series inductance path between the first and second nodes, or as a shunt inductance path between the ground and a node along the inductance path.

The present technology is directed to a system and method for implementing passive power harvesting from ambient electromagnetic emissions with a smart rectenna that incorporates automatic frequency response tuning features. The disclosed system incorporates a tunable High Pass Filter and voltage multiplier rectifier with a front-end ultra wide band antenna unit. The frequency response of tunable components can be actively adjusted to match the frequency band containing most of the energy in the incident electromagnetic emission. A look up table is used for determining the appropriate biasing levels of the tunable components for each frequency in a frequency band of interest. By tuning a frequency response of impedance matching, filtering and rectifying components to correspond to a frequency region of maximum power spectral density in the incident energy signal, the system facilitates the scavenging of ambient electromagnetic energy from the spectral region with the highest power spectral density.

A wireless communication device is described. The wireless communication device includes a processor, a memory in communication with the processor and instructions stored in the memory. The instructions are executable by the processor to detect a signal degradation indication for a radio frequency (RF) signal. The instructions are also executable by the processor to cause a switch to select a combination of a first matching network and a second matching network coupled to an antenna in response to detecting the signal degradation indication.

A radio-frequency module includes a first terminal configured to receive a signal from an antenna, a substrate, a first filter element on the substrate, a first switch including a first switch terminal and a second switch terminal connectable to the first switch terminal, and connected between the first terminal and the first filter element, and a second switch including a third switch terminal. The first filter element is connected between the second switch terminal and the third switch terminal, the first switch and the second switch are included in a semiconductor chip, and the semiconductor chip is on the substrate.

Embodiments relate to a transformer-based impedance matching network that may dynamically change its characteristic impedance by engaging different inductor branches on a primary side and optionally, on the secondary side. A primary side transformer circuit includes a primary inductor (311) and secondary inductor (321) configured to provide impedance matching over a first frequency band. One or more additional inductor branches (314A, 314B, are switchably coupled to either or both of the primary and secondary inductors to modify the impedance matching characteristics over additional operating frequencies. One or more LC filter branches (321, 322, 326, 327, 336, 330) can be included at the output of the secondary side to filter harmonic frequencies in each of the operating frequency bands.