A directional coupler is provided that includes a primary line that transmits signals from a first terminal to a second terminal; a secondary line that gets coupled with the primary line and draws some of the signals into a third terminal; a first switching unit that switches the connection destination of the third terminal between one end of the secondary line and the other end thereof; a first impedance regulating unit that is installed in between one end of the secondary line and the ground, and that changes the impedance according to the frequency of the signals; a second impedance regulating unit that is installed in between the other end of the secondary line and the ground, and changes the impedance according to the frequency of the signals; and a resonance circuit that is installed in between the first switching unit and the third terminal, and that changes the impedance of the third terminal according to the frequency of the signals.

Systems and methods for a tunable impedance are provided. A tunable impedance includes a transistor assembly having two terminals and a control input. The transistor assembly includes one or more transistors electrically connected between the two terminals to provide a first impedance between the two terminals, based upon a control signal. One or more replica transistors react to the control signal in a similar fashion as the transistor assembly, to provide a replica impedance based upon the control signal. A control circuit is configured to generate the control signal based upon a voltage across the replica transistor(s) and/or a current through the replica transistor(s).

A directional coupler includes a main line, a sub-line, a coupling terminal, a terminal circuit, a first switching circuit, and a second switching circuit. The first switching circuit and the second switching circuit respectively connects the first end and the second end of the sub-line alternately to the coupling terminal and to the terminal circuit. The first switching circuit connects the first end to the coupling terminal at a time that differs from a time at which the first switching circuit disconnects the first end from the terminal circuit. The first switching circuit disconnects the first end from the coupling terminal at a time that differs from a time at which the first switching circuit connects the first end to the terminal circuit.

A radio calibration system includes an FPGA that generates a calibration signal by a pseudo noise generator and mixes the calibration signal with a carrier generated by a carrier generator. The FPGA injects the calibration signal into an analog electronic device which couples the calibration signal into a receiver channel. The receiver channel measures calibration signal power, group delay, and phase, and performs calibration based on these measurements. A reference clock synchronizes the pseudo noise generator, the carrier generator and the receiver channel.

A resistive component in a hybrid microwave attenuator circuit is configured to attenuate a plurality of frequencies in an input signal. The hybrid microwave attenuator circuit is further configured with a dispersive component to attenuate a second plurality of frequencies within a frequency range by reflecting off portions of the input signal at those frequencies that are within the frequency range. The resistive component and the dispersive component are arranged in a series configuration relative to one another in the hybrid microwave attenuator circuit.

A coupling device includes a plurality of couplers, a first coupled output port and a second coupled output port, wherein the plurality of couplers comprise a first coupler and a second coupler that are adjacent one another, and each of the first coupler and the second coupler comprises a main line and a subline, and for each of the first coupler and the second coupler: the subline includes a first section, a second section, and a third section, wherein the second section of the subline of the first coupler has a common segment with the first section of the subline of the second coupler.

A power divider includes first to third transmission lines (TLs) and first to third capacitors. The second TL includes a first transmission portion (TP) and a first output portion (OP). The first TP is connected between the first TL and the first OP. The third TL includes a second TP and a second OP. The second TP is connected between the first TL and the second OP. The first capacitor is connected between ground and a common node of the first TL and the first and second TPs. The second capacitor is connected between ground and a terminal of the first OP distal from the first TP. The third capacitor is connected between ground and a terminal of the second OP distal from the second TP.

A directional coupler according to various embodiment and an electronic device having the same are provided. The directional coupler includes a first layer having at least one conductive portion, a second layer disposed adjacent to the first layer in a first direction and having at least one conductive plate corresponding to the conductive portion of the first layer, a third layer disposed adjacent to the second layer in the first direction and including an RF signal transmission line, a fourth layer disposed adjacent to the third layer in the first direction and having a conductive line wound with at least one turn, and at least one conductive via electrically connecting the at least one conductive plate of the second layer and the conductive line of the fourth layer which is wound with at least one turn.

Doherty power amplifiers with coupled line combiners are provided herein. In certain embodiments, a power amplifier system includes a carrier amplifier having a carrier output that provides a first radio frequency signal, a peaking amplifier having a peaking output that provides a second radio frequency signal, and a coupled line combiner including a first conductor line connected to the peaking output, a second conductor line electromagnetically coupled to the first conductor line, a third conductor line connected to the carrier output, and a fourth conductor line electromagnetically coupled to the third conductor line and in series with the second conductor line. The power amplifier system further includes an inductor in series with the fourth conductor line and the second conductor line and operable to provide a radio frequency output signal to an output terminal.

A coupling device includes a plurality of couplers, a first coupled output port and a second coupled output port, wherein the plurality of couplers comprise a first coupler and a second coupler that are adjacent one another, and each of the first coupler and the second coupler comprises a main line and a subline, and for each of the first coupler and the second coupler: the subline includes a first section, a second section, and a third section, wherein the second section of the subline of the first coupler has a common segment with the first section of the subline of the second coupler.