The present invention provides a terahertz oscillator utilizing a GaN Gunn diode. A terahertz wave is generated in the active layer of the Gunn diode fabricated on GaN substrate. A GaN substrate is designed to act as a waveguide of the terahertz wave. Since the waveguide and the Gunn diodes are integrated, the terahertz wave generated in the active layer couples well with the waveguide made of the GaN substrates. The terahertz wave is emitted from the edge of the waveguide efficiently. To ensure high-reliability through reduction of radiation loss and mitigation of electromigration of anode metal, a GaN substrate with low dislocation density is used. The dislocation density of the GaN substrate is less than 1×10.sup.6 cm.sup.−2. Particularly, usage of a GaN substrate made by the ammonothermal method is preferred.

The present invention provides a terahertz oscillator utilizing a GaN Gunn diode. A terahertz wave is generated in the active layer of the Gunn diode fabricated on GaN substrate. A GaN substrate is designed to act as a waveguide of the terahertz wave. Since the waveguide and the Gunn diodes are integrated, the terahertz wave generated in the active layer couples well with the waveguide made of the GaN substrates. The terahertz wave is emitted from the edge of the waveguide efficiently. To ensure high-reliability through reduction of radiation loss and mitigation of electromigration of anode metal, a GaN substrate with low dislocation density is used. The dislocation density of the GaN substrate is less than 1×10.sup.6 cm.sup.−2. Particularly, usage of a GaN substrate made by the ammonothermal method is preferred.

A device, comprising: an antenna array provided with a plurality of antennas each having a semiconductor layer having terahertz-wave gain; and a coupling line for mutual frequency-locking of at least two of the antennas at a frequency of the terahertz-wave, wherein the coupling line is connected to a shunt device, and the shunt device is connected in parallel to the semiconductor layer of each of the two antennas.

A device includes a first antenna arranged on a substrate, with the first antenna comprising a first semiconductor layer having terahertz-wave gain and a first conductor layer, a second antenna arranged on the substrate, with the second antenna comprising a second semiconductor layer having terahertz-wave gain and a second conductor layer, and a third conductor layer arranged on the substrate and electrically connecting the first antenna and the second antenna. A shunt device is arranged on the substrate and electrically connected to the third conductor layer. In planar view, the shunt device does not overlap with at least the first conductor layer.

Apparatus and methods for power amplifiers with an injection-locked oscillator driver stage are provided herein. In certain configurations, a multi-mode power amplifier includes a driver stage implemented using an injection-locked oscillator and an output stage having an adjustable supply voltage that changes based on a mode of the multi-mode power amplifier. By implementing the multi-mode power amplifier in this manner, the multi-mode power amplifier exhibits excellent efficiency, including when the voltage level of the adjustable supply voltage is relatively low.

Apparatus and methods for power amplifiers with an injection-locked oscillator driver stage are provided herein. In certain configurations, a multi-mode power amplifier includes a driver stage implemented using an injection-locked oscillator and an output stage having an adjustable supply voltage that changes based on a mode of the multi-mode power amplifier. By implementing the multi-mode power amplifier in this manner, the multi-mode power amplifier exhibits excellent efficiency, including when the voltage level of the adjustable supply voltage is relatively low.

The present invention provides a terahertz oscillator utilizing a GaN Gunn diode. A terahertz wave is generated in the active layer of the Gunn diode fabricated on GaN substrate. A GaN substrate is designed to act as a waveguide of the terahertz wave. Since the waveguide and the Gunn diodes are integrated, the terahertz wave generated in the active layer couples well with the waveguide made of the GaN substrates. The terahertz wave is emitted from the edge of the waveguide efficiently. To ensure high-reliability through reduction of radiation loss and mitigation of electromigration of anode metal, a GaN substrate with low dislocation density is used. The dislocation density of the GaN substrate is less than 1×10.sup.6 cm.sup.−2. Particularly, usage of a GaN substrate made by the ammonothermal method is preferred.

The present invention provides a terahertz oscillator utilizing a GaN Gunn diode. A terahertz wave is generated in the active layer of the Gunn diode fabricated on GaN substrate. A GaN substrate is designed to act as a waveguide of the terahertz wave. Since the waveguide and the Gunn diodes are integrated, the terahertz wave generated in the active layer couples well with the waveguide made of the GaN substrates. The terahertz wave is emitted from the edge of the waveguide efficiently. To ensure high-reliability through reduction of radiation loss and mitigation of electromigration of anode metal, a GaN substrate with low dislocation density is used. The dislocation density of the GaN substrate is less than 1×10.sup.6 cm.sup.−2. Particularly, usage of a GaN substrate made by the ammonothermal method is preferred.

A differential constructive wave oscillator device including a single, continuous differential transmission line that is arranged into first and second parallel traces in the form of a Mobius loop. The continuous transmission line includes first and second crossover points, each of which provides for a point of inflection between the first and second traces. In each stage of the device, both the first and second traces of the transmission line carry the forward traveling wave signal from a differential input port to a differential output port. Each phase includes a differential delay section that provides for a phase shift between a signal on the first trace and a signal on the second trace. Each phase additionally includes a differential feedback amplifier that amplifies the forward traveling wave signal at the differential output port, generates a differential feedback signal, and routes the differential feedback signal to the differential input port.

A differential constructive wave oscillator device including a single, continuous differential transmission line that is arranged into first and second parallel traces in the form of a Mobius loop. The continuous transmission line includes first and second crossover points, each of which provides for a point of inflection between the first and second traces. In each stage of the device, both the first and second traces of the transmission line carry the forward traveling wave signal from a differential input port to a differential output port. Each phase includes a differential delay section that provides for a phase shift between a signal on the first trace and a signal on the second trace. Each phase additionally includes a differential feedback amplifier that amplifies the forward traveling wave signal at the differential output port, generates a differential feedback signal, and routes the differential feedback signal to the differential input port.