Disclosed is an electronic device comprising: a wireless communication circuit for generating an RF signal, an amplifier circuit electrically connected to the wireless communication circuit and configured to amplify the RF signal, and an antenna connected to the amplifier circuit. The amplifier circuit may comprise: a first amplifier; a second amplifier; a first transmission path connected to an output terminal of the first amplifier and the antenna; a second transmission path connected to an output terminal of the second amplifier and the first transmission path; a first variable impedance circuit located on the first transmission path and configured to change an electrical length of the first transmission path based on the frequency of the RF signal; and a second variable impedance circuit located on the second transmission path and configured to change the electrical length based on a power mode.

An amplifier (300) comprising: a first signal path comprising first amplifier circuitry (105A) configured to receive a first signal (RF1) with a frequency and a variable phase and amplitude at the frequency; a second signal path comprising second amplifier circuitry (105B) configured to receive a second signal (RF2) with the frequency, wherein at least one of the relative phase and amplitude of the second signal is fixed at the frequency; combiner circuitry (106) configured to combine an output of the first amplifier circuitry and the second amplifier circuitry.

A power amplifier arrangement (100) for amplifying an input signal (Pin) to produce an output signal (Pout) is disclosed. The amplifier arrangement (100) comprise an input port (IN) for receiving the input signal; an output transmission line (110) having a first terminal (111) and a second terminal (112); an output port (OUT) coupled to the second terminal (112) of the output transmission line (110) for providing the output signal; and a plurality N of amplifying devices (121, 122, . . . 12N) distributed along the output transmission line (110). The power amplifier arrangement (100) is configured such that the plurality N of amplifying devices are active sequentially for amplifying the input signal with increasing amplitude of the input signal.

Methods and apparatus are provided. In an example aspect, a method of operating an amplifier circuit is provided. The amplifier circuit comprises a first amplifier configured to receive a first signal, a balanced amplifier comprising second and third amplifiers and configured to receive a second signal, and a first directional coupler. An output of the first amplifier is connected to a transmitted port of the first directional coupler, an output of the second amplifier is connected to an input port of the first directional coupler, an output of the third amplifier is connected to an isolated port of the first directional coupler, and a coupled port of the first directional coupler is connected to an output of the amplifier circuit. The method comprises operating the amplifier circuit in a first output peak amplitude range of the amplifier circuit wherein, in the first output peak amplitude range, the first signal is based on a signal to be amplified and has an amplitude that increases across the first output peak amplitude range from substantially zero to a first amplitude, and the second signal is substantially zero, and operating the amplifier circuit in a second output peak amplitude range of the amplifier circuit, wherein the second output peak amplitude range is higher than the first output peak amplitude range and wherein, in the second output peak amplitude range, the first signal is based on the signal to be amplified and has an amplitude that decreases across the second output peak amplitude range from the first amplitude to a second amplitude, and the second signal is based on the signal to be amplified and has an amplitude that increases across the second output peak amplitude range from a third amplitude to a fourth amplitude.

Methods and apparatus are provided. In an example aspect, a method of operating an amplifier circuit is provided. The amplifier circuit comprises a first amplifier configured to receive a first signal, a balanced amplifier comprising second and third amplifiers and configured to receive a second signal, and a first directional coupler. An output of the first amplifier is connected to a transmitted port of the first directional coupler, an output of the second amplifier is connected to an input port of the first directional coupler, an output of the third amplifier is connected to an isolated port of the first directional coupler, and a coupled port of the first directional coupler is connected to an output of the amplifier circuit. The method comprises operating the amplifier circuit in a first output peak amplitude range of the amplifier circuit wherein, in the first output peak amplitude range, the first signal is based on a signal to be amplified and has an amplitude that increases across the first output peak amplitude range from substantially zero to a first amplitude, and the second signal is substantially zero, and operating the amplifier circuit in a second output peak amplitude range of the amplifier circuit, wherein the second output peak amplitude range is higher than the first output peak amplitude range and wherein, in the second output peak amplitude range, the first signal is based on the signal to be amplified and has an amplitude that decreases across the second output peak amplitude range from the first amplitude to a second amplitude, and the second signal is based on the signal to be amplified and has an amplitude that increases across the second output peak amplitude range from a third amplitude to a fourth amplitude.

An on-chip transformer circuit is disclosed. The on-chip transformer circuit comprises a primary winding circuit comprising at least one turn of a primary conductive winding arranged as a first N-sided polygon in a first dielectric layer of a substrate; and a secondary winding circuit comprising at least one turn of a secondary conductive winding arranged as a second N-sided polygon in a second, different, dielectric layer of the substrate. In some embodiments, the primary winding circuit and the secondary winding circuit are arranged to overlap one another at predetermined locations along the primary conductive winding and the secondary conductive winding, wherein the predetermined locations comprise a number of locations less than all locations along the primary conductive winding and the secondary conductive winding.

A radio-frequency (RF) splitter is provided. The RF splitter includes a common branch node configured to transfer an RF signal, input from an input port, to at least one of first and second output ports, first and second branch nodes electrically connected between the common branch node and the first and second output ports, first and second series switches configured to control switching operations to electrically connect the common branch node and the first and second branch nodes to each other, first and second inductors electrically connected between the common branch node and the first and second branch nodes, a resistor electrically connected between the first and second branch nodes, and first and second shunt switches configured to control switching operations to electrically connect the first and second branch nodes and the resistor to each other.

Disclosed is a frequency-dependent microwave filter (1). The filter (1) comprises an enclosure (11) comprising a filter medium including at least one constituent of: atoms, molecules, ions, and point defects in an optically pumpable solid. The at least one constituent is excitable to an initial energy state. The filter (1) further comprises a field generator (12) configured to generate an inhomogeneous electric and/or magnetic field (12A) within the enclosure (11). The filter (1) further comprises means (13) for feedthrough of a microwave signal through the enclosure (11) and an optical pump (14) configured to periodically excite the at least one constituent of the filter medium to the initial energy state in alternation with the feedthrough of the microwave signal through the enclosure (11). Thereby, intensity-dependent filtering is achieved.

Disclosed is a frequency-dependent microwave filter (1). The filter (1) comprises an enclosure (11) comprising a filter medium including at least one constituent of: atoms, molecules, ions, and point defects in an optically pumpable solid. The at least one constituent is excitable to an initial energy state. The filter (1) further comprises a field generator (12) configured to generate an inhomogeneous electric and/or magnetic field (12A) within the enclosure (11). The filter (1) further comprises means (13) for feedthrough of a microwave signal through the enclosure (11) and an optical pump (14) configured to periodically excite the at least one constituent of the filter medium to the initial energy state in alternation with the feedthrough of the microwave signal through the enclosure (11). Thereby, intensity-dependent filtering is achieved.

A load modulation amplifier is disclosed having a first amplifier and a second amplifier. An input quadrature coupler and an output quadrature coupler are coupled between the first amplifier and the second amplifier. A splitter has a first splitter output, a splitter input coupled to a signal input, and a second splitter output coupled to a second port of the input quadrature coupler, and a variable attenuator is coupled between the first splitter output and a first port of the input quadrature coupler. An attenuation controller has a controller output that is coupled to an attenuation control input of the variable attenuator, wherein the attenuation controller autonomously generates a control signal in response to a power sample signal in proportion to a radio frequency signal received at the radio frequency signal input.