Abstract: A device comprising a two-dimensional electron gas that includes an active region located in a portion of the electron gas is disclosed. The active region comprises an electron concentration less than an electron concentration of a set of non-active regions of the electron gas. The device includes a controlling terminal located on a first side of the active region. The device can comprise, for example, a field effect transistor (FET) in which the gate is located and used to control the carrier injection into the active region and define the boundary condition for the electric field distribution within the active region. The device can be used to generate, amplify, filter, and/or detect electromagnetic radiation of radio frequency (RF) and/or terahertz (THz) frequencies.

Abstract: A switch circuit is provided that includes at least one main switching device and at least one shunt switching device. Each main switching device is connected in series with a conductor that carries an RF signal between an input circuit and an output circuit. Each shunt switching device is connected between a controlling terminal of the main switching device and a high frequency ground. The switch circuit can provide substantially improved OFF state isolation over other approaches.

Abstract: A two-stage amplifier is provided, which in the first stage, a first amplifier generates a non-linear square wave based on a harmonic input. The non-linear square wave has the same frequency as the harmonic input and is provided as an input to the second stage, in which a second amplifier generates an amplified harmonic output. The first amplifier and/or second amplifier can comprise a group-III nitride-based Heterostructure Field Effect Transistor (HFET). Additionally, the first amplifier can comprise a multi-harmonic Class F amplifier and the second amplifier can comprise a Class E amplifier.

Abstract: A field effect transistor (FET) comprising a gate structure that includes at least one gate having a varying sheet resistance in a direction between a source contact and a drain contact. In an illustrative embodiment, the FET can be configured to operate as a radio frequency switch. In this case, the FET can provide improved performance with respect to both the off-state capacitances and radio frequency isolations over similar FETs implemented with typical gates.

Abstract: The current invention introduces a modulated field element incorporated into the semiconductor device outside the controlling electrode and active areas. This element changes its conductivity and/or dielectric properties depending on the electrical potentials of the interface or interfaces between the modulated field element and the semiconductor device and/or incident electromagnetic radiation. The element is either connected to only one terminal of the semiconductor device, or not connected to any terminal of a semiconductor device nor to its active area(s). Such an element can be used as modulated field plate, or a part of a field plate, as a passivation layer or its part, as a guard ring or its part, as a smart field or charge control element or its part, as a feedback element or its part, as a sensor element or its part, as an additional electrode or its part, as an electromagnetic signal path or its part, and/or for any other functions optimizing or modernizing device performance.

Abstract: A field effect transistor that can be operated as a low voltage Class FN radio frequency (RF) amplifier with harmonic tuning is provided. The field effect transistor includes a common electrode, a gate, and multiple separate electrodes. The common electrode can comprise a source or drain, while the separate electrodes can comprise drains or sources, respectively. The gate can be profiled in a manner that forms multiple gate sections, each having a unique gate length within the gate sections. Each separate electrode can correspond to one of the plurality of gate sections. When operated as a Class FN RF amplifier with a linear harmonic input, the output signal will comprise a non-linear square wave with sharp fronts and relatively flat peak states.

Abstract: A two-stage amplifier is provided, which in the first stage, a first amplifier generates a non-linear square wave based on a harmonic input. The non-linear square wave has the same frequency as the harmonic input and is provided as an input to the second stage, in which a second amplifier generates an amplified harmonic output. The first amplifier and/or second amplifier can comprise a group-III nitride-based Heterostructure Field Effect Transistor (HFET). Additionally, the first amplifier can comprise a multi-harmonic Class F amplifier and the second amplifier can comprise a Class E amplifier.