A wide band radio frequency (RF) circulator, including: a first stage having four ports; and a second stage having four ports, wherein the first stage and the second stage are connected via a pair of conductive delay lines including a reciprocal delay line placed on a dielectric substrate and a non-reciprocal delay line placed on ferrite substrate, wherein each of the first stage and the second stage include a pair of couplers.

An adjustable sensing capacitance microelectromechanical system (MEMS) apparatus includes an ASIC and a sensing component. The ASIC includes a top surface, a readout circuit and a plurality of electrical switches. The sensing component, configured to sensing physical quantity, includes a fixed electrode and a movable electrode. The fixed electrode includes a plurality of electrode units. The movable electrode is able to be moved relative to the fixed electrode. The electrical switches are respectively and electrically coupled to the electrode units so as to control a working status of each of the electrode units, thereby changing a sensing capacitance of the MEMS sensor.

The present disclosure may include, for example, a tunable capacitor having a decoder for generating a plurality of control signals, and an array of tunable switched capacitors comprising a plurality of fixed capacitors coupled to a plurality of switches. The plurality of switches can be controlled by the plurality of control signals to manage a tunable range of reactance of the array of tunable switched capacitors. Additionally, the array of tunable switched capacitors is adapted to have non-uniform quality (Q) factors. Additional embodiments are disclosed.

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 are various embodiments for controlling the operation of a guided surface waveguide probe. A control system coupled to the guided surface waveguide probe can monitor and control the guided surface waveguide probe and one or more subsystems associated with the guided surface waveguide probe. Based on data collected from the guided surface waveguide probe and/or the various subsystems, the control system can adjust the operation of the guided surface waveguide probe. Human operators can interact with the control system at a location outside of a safety perimeter surrounding the guided surface waveguide probe.

A coupling circuit for power line communications includes a coupling transformer having first and second mutually coupled windings, with the first winding connectable to a power line. The second winding includes a pair of intermediate taps with one or more tuning inductor therebetween. The inductor or inductors are set between a first portion and a second portion of the second winding of the coupling transformer. A switch member is provided coupled with the inductor. The switch member is selectively actuatable to short-circuit the inductor.

A balun includes a first winding which has a first terminal coupled to an input, and a second terminal coupled to a reference potential terminal. The balun includes a second winding magnetically coupled to the first winding. The second winding has a first terminal coupled to a first differential output, a second terminal coupled to a second differential output, and a tap coupled to the reference potential terminal. The balun includes a first capacitor which has a first terminal coupled to the first winding and a second terminal coupled to the second winding. The balun includes a third winding which has a first terminal coupled to the reference potential terminal and a floating second terminal. The balun includes a second capacitor which has a first terminal coupled to the third winding and a second terminal coupled to the second winding.

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 fist 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.

A balun includes a first winding which has a first terminal coupled to an input, and a second terminal coupled to a reference potential terminal. The balun includes a second winding magnetically coupled to the first winding. The second winding has a first terminal coupled to a first differential output, a second terminal coupled to a second differential output, and a tap coupled to the reference potential terminal. The balun includes a first capacitor which has a first terminal coupled to the first winding and a second terminal coupled to the second winding. The balun includes a third winding which has a first terminal coupled to the reference potential terminal and a floating second terminal. The balun includes a second capacitor which has a first terminal coupled to the third winding and a second terminal coupled to the second winding.

A transformer includes: a rotary shaft configured to rotate about a central axis of the rotary shaft as a rotational axis; a primary-side first coil configured to extend around a first axis perpendicular to the central axis; a secondary-side second coil configured to extend around a second axis and supported by the rotary shaft, the second axis being perpendicular to the rotational axis in an area surrounded by the first coil; and a secondary-side third coil configured to extend around a third axis and supported by the rotary shaft, the third axis being perpendicular to the rotational axis and forming a predetermined angle with the second axis in the area.