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Terahertz (THz) wave frequency region is part of the electromagnetic spectrum. This spectrum is located between 0.3 THz to 10 THz or between radio waves and optics. The THz frequency region has potentials in many different applications, such as imaging, spectroscopy, and wireless communication. However, some problems are still remaining and should be solved to develop THz technology system for an...
In this paper, a rectangular shaped Terahertz (THz) microstrip patch antenna with a slotted ground has been proposed. The Flame Retardant (FR-4) having a dielectric constant (∊r) of 4.4. The copper having a resistivity of 1.68 × 10−8 Ωm has been employed in the designing of the proposed antenna. A slot of rectangular shape has been made in the ground for enhancing the various antenna parameters. The...
Planar nano-diodes fabricated on an AlGaN/GaN heterolayer have been measured, showing capability to detect microwave signals up to 43.5 GHz at room temperature. A single nano-diode with length L=1000 nm and width W=74 nm provides a response of approximately 55 mV DC output for a 0 dBm nominal input power at 1 GHz, with a very small fraction of the RF power reaching effectively the device due to a...
The preliminary design and particle simulation of high-frequency structure for 310GHz extended interaction klystron (EIK) with folded waveguide (FWG) as the resonant cavity was presented in this paper The validity of FWG slow-wave structure (SWS) as EIK resonant cavity was demonstrated. The simulation indicated that FWG cavities have high characteristic impedance and can generate high gain amplification...
Folded waveguide is a promising structure for THz travelling wave tube (TWT) application. In this paper, a folded waveguide slow-wave structure of 220GHz TWT is designed and simulated using CST Microwave Studio and Particle Studio. Interaction impedance and dispersion relation vs. frequency are evaluated. The relationship between gain and parameters such as beam current, electron's emitting angle,...
We present the responsivity spectra in the 0.2–0.4 THz range at low temperature of a AlGaAs/GaAs field-effect transistor connected to an on-chip integrated antenna. We fabricated asymmetric plasmonic microcavities to obtain down-converted signals from the intrinsic nonlinearity of 2D electron plasma oscillations. Finite-element modeling simulations of the 2D electron oscillations and electromagnetic...
A 1 THz vacuum electronic source has been designed and implemented by Particle-in-cell (PIC) simulation based on rectangular grating slow-wave structure (SWS) and half duty cycle electron beam. The dispersion relation and coupling impedance are analyzed numerically. The simulation results predict that this designed 1 THz vacuum source can produce maximum 102 W saturated power at the end of structure...
A graphene-based archimedean spiral antenna is numerically studied. The input impedance and the radiation properties of such antenna are investigated through full-wave numerical simulations. Simulations show that the proposed structure allows frequency reconfiguration as well as appropriate radiation resistance to diminish the mismatch between antenna and photomixer. It is also shown that the total...
A switchable THz absorber, with absorbance more than 90% is proposed, and numerically characterized. The absorber structure is based on metamaterials with unit cells consisting of two patterned graphene layers separated by a 5-nm thick layer of Al2O3. Numerical results show that when the chemical potential of the top graphene microribbons are tuned by an external variable bias and that of the lower...
Graphene, with its distinctive and outstanding optoelectronic properties, has prompted its use in a wide variety of applications such as transparent conductive electrodes and modulators. Recently, due to advances in graphene synthesis methods, large-area graphene field effect transistors (GFET) have displayed unique modulation of terahertz waves. By transferring chemical vapor deposited graphene films...
Graphene, with its distinctive and outstanding optoelectronic properties, has prompted its use in a wide variety of applications such as transparent conductive electrodes and modulators. Recently, due to advances in graphene synthesis methods, large-area graphene field effect transistors (GFET) have displayed unique modulation of terahertz waves. By transferring chemical vapor deposited graphene films...
A 300-GHz probe-type microstrip-to-waveguide transition in low-temperature co-fired ceramic (LTCC) is presented. A via fence and air holes are used to form a three-dimensional impedance-matching structure and a vertical hollow waveguide inside the multi-layer LTCC substrate. By incorporating the air-hole matching structure beside the microstrip probe, the bandwidth is enhanced. A prototype of the...
A novel broadband technique to effectively launch plasmons along a single graphene layer at terahertz (THz) frequencies is proposed. To this end, the coupling of the electromagnetic wave from a readily available plasmonic waveguide established by a periodically corrugated metallic surface to the graphene sheet is proposed. As will be shown, this technique can significantly surmount the need for efficient...
A dipole-like antenna made of graphene strips and integrated with a THz photonic mixer is studied numerically. The input impedance and the radiation properties of such graphene-based antenna are investigated through full-wave numerical simulations. Full-wave simulations show that the graphene-based antennas can provide higher input impedance along with the tunability of the resonance frequency; however,...
A slotted single-grating rectangular waveguide is proposed as the SWS of a novel 0.65 THz BWO. Utilizing HFSS, the cold electromagnetic performance of the SWS is studied. Input/output structure is designed. This BWO is verified by a 3-D particle-in-cell simulation using MAFIA. A 0.88W peak output power at 0.65THz is obtained under 12-kV operating voltage and 7-mA beam current.
In this paper, electromagnetic field simulations and related results of a 400 GHz central frequency microfabricated folded waveguide traveling-wave tube were presented, for a broadband terahertz amplifier. 3-D cold-test (absence of real electron beam) and particle-in-cell simulations were carried out. Two models of different beam tunnel cross-section, i.e. cylindrical and rectangular, were simulated...
A design approach of Lange coupler for Si-substrate monolithic microwave integrated circuits is presented for frequency range up to 170 GHz. A combination of odd- and even-mode impedance theory and 3D EM simulation is proposed to improve the performance of Lange coupler. The value of the even number of the strip lines is determined based on the even-mode impedance calculation according to the process...
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