An electromagnetic coupler apparatus includes a plurality of couplers, each having a coupled port and an isolation port. The coupler apparatus includes an output port configured to provide a coupled signal from one or more of the plurality of couplers, and a number of selection control inputs. Each of the selection control inputs is configured to control one or more switches to select an individual one of the plurality of couplers to provide at least a portion of the coupled signal at the output port.

Certain aspects of the present disclosure provide a circuit for dividing or combining power. The circuit generally includes a Wilkinson power divider, a first capacitive element, and a first resistive element coupled in parallel with the first capacitive element, wherein the first capacitive element and the first resistive element are coupled between a first port of the circuit and a first port of the Wilkinson power divider.

Aspects of the disclosure are directed to auto-sweeping impedance-matching circuitry that matches an impedance of an RF antenna. As may be implemented in accordance with one or more embodiments, a transmitter that is configured and arranged to transmit signals to remote devices via the RF antenna, is used to communicate a plurality of test signals to the impedance-matching circuitry, with each test signal having a designated frequency and/or test signal pattern that is different than the designated frequency and/or test signal pattern of the other test signals. A characteristic of each of the test signals as passed through the impedance-matching circuitry is detected. For each of the test signals generated for the auto-sweep, the detected characteristic is compared to an expected characteristic for the test signal, and an output indicative of compliance of the impedance-matching circuitry with a design specification is generated and transmitted in response to the comparison.

A tapped transmission line for distributing an electrical signal, such as an RF signal, to multiple modules, and/or aggregating signals from multiple modules. Embodiments of the invention provide a tapped transmission line based on a transmission-line medium along which tap elements are dispersed, so that the tap elements have a predominantly capacitive loading of the transmission-line medium. Methods for compensating the loss of the transmission-line medium are presented as well. Applications for distribution of transmitted signals, of local oscillator signals, and to aggregation of signals from multiple oscillators are disclosed. The invention is particularly applicable to integrated circuits (IC, ASIC, RFIC), and to multichannel RF systems such as phased array and MIMO systems.

Transmission-line filtering with enhanced frequency response is disclosed. In an example aspect, an apparatus includes a transmission-line filter to enhance a frequency response of a filtering operation. The transmission-line filter includes an input port, an output port, and multiple transmission-line base units. The multiple transmission-line base units are disposed between the input port and the output port and are coupled to the input port and the output port. Each of the multiple transmission-line base units includes a respective transmission line of multiple transmission lines. At least one transmission-line base unit of the multiple transmission-line base units includes a multi-resonant circuit.

Certain aspects of the present disclosure provide a directional coupler. In certain aspects, the directional coupler generally includes a first inductor and a second inductor wirelessly coupled to the first inductor. In certain aspects, the directional coupler generally includes an input port at a first terminal of the first inductor and a transmitted port at a second terminal of the first inductor. In certain aspects, the directional coupler generally includes a coupled port at a first terminal of the second inductor and an isolated port at a second terminal of the second inductor. In certain aspects, the directional coupler generally includes a first complex impedance component directly coupled to the isolated port and a second complex impedance component directly coupled to the coupled port.

Certain aspects of the present disclosure provide a circuit for dividing or combining power. The circuit generally includes a Wilkinson power divider, a first capacitive element, and a first resistive element coupled in parallel with the first capacitive element, wherein the first capacitive element and the first resistive element are coupled between a first port of the circuit and a first port of the Wilkinson power divider.

A tapped transmission line for distributing an electrical signal, such as an RF signal, to multiple modules, and/or aggregating signals from multiple modules. Embodiments of the invention provide a tapped transmission line based on a transmission-line medium along which tap elements are dispersed, so that the tap elements have a predominantly capacitive loading of the transmission-line medium. Methods for compensating the loss of the transmission-line medium are presented as well. Applications for distribution of transmitted signals, of local oscillator signals, and to aggregation of signals from multiple oscillators are disclosed. The invention is particularly applicable to integrated circuits (IC, ASIC, RFIC), and to multichannel RF systems such as phased array and MIMO systems.

An apparatus for a network matching switch is provided. The apparatus includes a primary winding, a first secondary winding, a second secondary winding and a plurality of matching network paths. The primary winding is configured to generate a magnetic field based on an analog input signal. The first secondary winding is configured is inductively coupled to the primary winding. The second secondary winding is inductively coupled to the primary winding. The plurality of matching network paths are coupled to the first secondary winding and the second secondary winding. An active path is selected from the plurality of matching network paths and provides power to an active load.

Aspects of the disclosure are directed to auto-sweeping impedance-matching circuitry that matches an impedance of an RF antenna. As may be implemented in accordance with one or more embodiments, a transmitter that is configured and arranged to transmit signals to remote devices via the RF antenna, is used to communicate a plurality of test signals to the impedance-matching circuitry, with each test signal having a designated frequency and/or test signal pattern that is different than the designated frequency and/or test signal pattern of the other test signals. A characteristic of each of the test signals as passed through the impedance-matching circuitry is detected. For each of the test signals generated for the auto-sweep, the detected characteristic is compared to an expected characteristic for the test signal, and an output indicative of compliance of the impedance-matching circuitry with a design specification is generated and transmitted in response to the comparison.