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.

An oscillator oscillating a tera hertz wave includes a negative resistive element including a first semiconductor layer, a second semiconductor layer, and an active layer disposed between the first semiconductor layer and the second semiconductor layer, with a first conductor, a second conductor, and a dielectric disposed between the first conductor and the second conductor constitutes a resonator, wherein the negative resistive element is disposed between the first conductor and the second conductor, and a layer with a higher resistivity than the first semiconductor layer or the second semiconductor layer, or an amorphous layer is disposed between the negative resistive element and the dielectric.

A device and method for terahertz signal generation are disclosed. Oscillators are arranged in a two-dimensional array, each oscillator connected to a corresponding antenna. Each oscillator is unidirectional connected to its adjacent oscillators by a phase shifter. A method for generating a steerable terahertz signal utilizes an array of oscillators connected by corresponding phase shifters. A terahertz signal having a fundamental frequency is generated using the array. The phase shift of one or more of the phase shifters is varied in order to vary the fundamental frequency and/or steer the signal generated by the array.

There is provided a terahertz device including: a terahertz element configured to generate an electromagnetic wave; a reflection film provided at a position facing the terahertz element and configured to reflect the electromagnetic wave generated from the terahertz element in one direction; and an encapsulating material configured to encapsulate the terahertz element and the reflection film.

THz device includes: a semiconductor substrate; a first semiconductor layer disposed on the semiconductor substrate; an active element formed by being laminated on the first semiconductor layer; a second electrode connected to the first semiconductor layer to be connected to a cathode K of the active element, the second electrode disposed on the semiconductor substrate; a first electrode connected to an anode A of the active element, the first electrode disposed on the semiconductor substrate to be opposite to the second electrode; a rear reflector metal layer disposed on a back side surface of the semiconductor substrate opposite to the first semiconductor layer, wherein the active element forms a resonator between the second and first electrodes, wherein electromagnetic waves are reflected on the rear reflector metal layer, and electromagnetic waves have a surface light-emission radiating pattern or surface light-receiving pattern in a vertical direction to the semiconductor substrate.

The apparatus comprises a first coupler configured to receive two output signals, having 180° phase difference, outputted from a first differential generator as two input signals, and output a first voltage signal generated by adding the two input signals and a second voltage signal corresponding to subtraction of the two input signals, a second coupler configured to receive two output signals, having 180° phase difference, outputted from a second differential generator as two input signals, and output a third voltage signal generated by adding the two input signals and a fourth voltage signal corresponding to subtraction of the two input signals, a coupling network connected to the first differential generator and the second differential generator and a third coupler configured to output a signal generated by adding the voltage signal outputted from the first coupler and corresponding voltage signal outputted from the second coupler.

A terahertz device includes a base member, a terahertz element, an antenna base, and a reflection film. The terahertz element is mounted on the base member and configured to generate an electromagnetic wave. The antenna base is located opposing the base member and includes an antenna surface. The reflection film is formed on the antenna surface to reflect at least part of the electromagnetic wave generated by the terahertz element in one direction.

An element includes a coupling line in which a first conductor layer, a dielectric layer, and a second conductor layer are stacked in this order, and which is connected to the second conductor layer in order to mutually synchronize a plurality of antennas at a frequency of a terahertz wave; and a bias line connecting a power supply for supplying a bias signal to a semiconductor layer and the second conductor layer. A wiring layer in which the coupling line is formed and a wiring layer in which the bias line is formed are different layers. The bias line is disposed in a layer between the first conductor layer and the second conductor layer.