A directional coupler disclosed herein may include a main line provided on a substrate, the main line having a first end connected to an input port and a second end connected to an output port. The coupler may include a coupled line disposed on the substrate, the coupled line having a first end connected to a coupled port and a second end to an isolated port. The main line is electrically isolated from the coupled line. The coupled line includes multiple turns forming a winding, and a portion of the winding overlaps with the main line. The coupled line forms a plurality of windings inductively coupled with the main line. The main line and the coupled line are routed to propagate electric signals on both lines in a same direction, and enhance inductive coupling by mutual inductance.

A load-insensitive power amplifier power detector that excludes the use of couplers is disclosed. The load-insensitive power amplifier power detector may include a voltage sampling circuit in electrical communication with a collector of a power amplifier and configured to sample a first voltage from the power amplifier. The load-insensitive power amplifier power detector may include a current sampling circuit in electrical communication with the collector of the power amplifier and configured to sample an output current from the power amplifier. Further, the load-insensitive power amplifier power detector may include a current-to-voltage converter connected between the voltage sampling circuit and an output of the load-insensitive power amplifier power detector. The current-to-voltage converter may be configured to convert the output current to obtain a second voltage. Moreover, a combination of the first voltage and the second voltage may form a detector voltage corresponding to an incident power of the power amplifier.

A digital microwave radio system includes a splitter that splits a common baseband input into two baseband outputs, first and second transmitters, each transmitter electrically connected to a baseband output of the splitter via a mixer, a common local oscillator electrically connected to the mixer of the first transmitter and the mixer of the second transmitter via an adjustable phase shifter, respectively, and a combiner. The common local oscillator is configured to up-convert each baseband output into a radio-frequency signal using a corresponding mixer. The combiner combines the two radio-frequency signals into a 0-degree phase-shift output and a 180-degree phase-shift output, respectively. A phase error control loop adjusts the phase shifter to minimize the 180-degree phase-shift radio-frequency output. A combiner gain control loop adjusts the output power level of the two transmitters in accordance with an actual power detector reading at the 0-degree phase-shift radio-frequency output.

A method of characterizing an envelope tracking amplification stage, the method comprising: generating an input test waveform which is representative of an input waveform under normal operating conditions of the amplification stage; applying a respective one of a plurality of different shaping functions, each comprising a non-linear transfer function, to the input signal envelope in each of a plurality of test periods during the period in which the input test waveform is applied as the input signal to generate the input to the envelope tracking modulated supply voltage; measuring parameters of the amplification stage during the period in which the input test waveform is applied in order to allow determination of the gain, phase and efficiency characteristics of the amplifier; and for each of the gain, phase and efficiency characteristics, generating a three dimensional plot of the characteristic with respect to input power and supply voltage applied to the amplifier.

An amplifier device for high frequency signals, in particular a linear high frequency amplifier device, which comprises at least one input, an incoming line, a pre-distortion unit, in particular an adaptive pre-distortion unit, an amplifier unit, in particular a non-linear power amplifier unit, a transmission line, a feedback unit, and an output. The output is connected to the amplifier unit via the transmission line. In addition, the at least one input is connected to the pre-distortion unit such that two incoming branch lines are provided which are interconnected by a switching unit. A first incoming branch line of the incoming branch lines comprises a down-converter being arranged between the at least one input and the pre-distortion unit.

Aspects of this disclosure relate to detecting power associated with an individual carrier of a carrier aggregated signal. In an embodiment, an aggregated carrier including at least a first carrier and a second carrier is provided. An indication of power of the first carrier of the aggregated carrier is detected. Separately from detecting the indication of power of the first carrier, an indication of power of the second carrier of the aggregated carrier is detected. The power associated with a radio frequency (RF) signal provided to an RF source associated with the first carrier can be adjusted based on the indication of power of the first carrier.

A voltage detecting apparatus includes a signal extracting circuit configured to extract a coupled signal from a signal output by a power amplifier configured to amplify a signal output by a radio frequency (RF) circuit, and a voltage detecting circuit configured to detect a detection voltage from the coupled signal and provide the detection voltage to the RF circuit. The voltage detecting circuit configured to vary the detection voltage in response to an input control signal.

The present invention provides an RF power amplifier architecture which with dynamic digital control of the amplification by incorporating digitized RF input and output signal envelope data and environmental temperature sensor(s) readings into an arbitrary control algorithm implemented on a digital processor. Via the combination of digitally controlled DC/DC converter and a D/A converter, the quiescent bias of the power FET of the RF output stage can become a realization of virtually any function of the feedback and input data.

A wide band directional coupler is disclosed. The coupler includes a main transmission line connected between an input port and an output port; and a coupling transmission line having a first length and connected between a coupling port and an isolation port, wherein the coupling transmission line is coupled to the main transmission line through a coupling capacitive connection and a mutual inductive connection, wherein at least a distance between the main transmission line and the coupling transmission line varies along the first length of the coupling transmission line such that any one of a capacitance value of the capacitive connection and an inductance value of the inductive connection is characterized by a relatively low value, wherein a coupling factor of the wide band directional couple remains substantially constant throughout an operating frequency band of the wide band directional coupler.

Optimized impedance characteristics of a variable impedance device causes the apparatus to transmit wireless signals with minimal out-of-band transmission at an optimized efficiency of the power amplifier. The variation of impedance characteristics of an antenna cause a change in the coefficients of a mapping function. The relatively fast variations to the power supply voltage of a power amplifier are applied to the mapping function to generate control signals which vary the impedance characteristics of a variable impedance device. The output of the mapping function includes control signals that control optimized impedance characteristics of a variable impedance device as a function of the variation of the supply voltage to a power amplifier. The coefficients of the mapping function may be regularly determined based on a comparison of out-of-band power and in-band power transmitted by an antenna.