Gyrotron and Vacuum Electronics Research

This letter describes the use of THz time-domain spectroscopy (TDS) applied in transmission to the secondary explosive 1,3,5 trinitro-s-triazine. Samples were also subjected to Fourier transform infrared spectroscopy over the same range for comparison. A detailed spectroscopy study is presented. General agreement betw…

• HAKAN ALTAN

Silicon carbide is a wide-band-gap semiconductor suitable for high-power high-voltage devices and it has excellent properties for use in photoconductive semiconductor switches (PCSSs). PCSS were fabricated as planar structures on high-resistivity 4H–SiC and tested at dc bias voltages up to 1000 V. The typical maximum…

• ALİ TEKE

A novel dual-mode microstrip square loop resonator is proposed using the slow-wave and dispersion features of the microstrip slow-wave open-loop resonator. It is shown that the designed and fabricated dual-mode microstrip filter has a wide stopband including the first spurious resonance frequency. Also, it has a size…

• ADNAN GÖRÜR

We propose a surface-emitted cavity configuration for a terahertz-wave parametric oscillator that allows THz wave emission perpendicular to the crystal surface without any output coupler. The oscillating idler and pump waves are reflected at the surface of a nonlinear crystal in a single resonance cavity, satisfying t…

A novel coplanar slow-wave structure that has the form of an interdigitated-meander line is proposed in this letter for use in MMIC's. A simple analysis of this structure has been carried out by using empirical equations available in the literature and with the aid of CAD packages. A propagation velocity of about 2.8/…

• ADNAN GÖRÜR

Considered is the beam wave guidance and scattering by 2D quasi-optical reflectors modeling the components of beam waveguides. The incident field is taken as the complex-source-point field to simulate a finite-width beam generated by a small-aperture source. A numerical solution is obtained from the coupled singular i…

A technique is developed for the efficient modeling of propagation over long paths (hundreds of lambda) by breaking the path up into segments and appropriately applying the perfectly matched layer (PML) absorbing boundary condition and the total field/scattered field boundary condition. For finite-difference time-doma…

• UMRAN SAVAŞ İNAN

In time hopping impulse radio, Nfpulses of duration Tcare transmitted for each information symbol. This gives rise to two types of processing gains: (i) pulse combining gain, which is a factor Nf, and (ii) pulse spreading gain, which is Nc= Tf/Tc, where Tfis the mean interval between two subsequent pulses. This paper…

We propose and experimentally demonstrate ultrawideband monocycle pulse generation using nondegenerate two-photon absorption in a silicon waveguide. The free-carrier absorption induced pulse tail at the rising edge of inverted probe pulse is largely compensated by the overlapped pump pulse and results in a symmetric n…

Despite the popularity and ubiquity of the tilted-pulse-front technique for single-cycle terahertz (THz) pulse generation, there is a deficit of experimental studies comprehensively mapping out the dependence of the performance on key setup parameters. The most critical parameters include the pulse-front tilt, the eff…

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• TURGUT ÖZTÜRK

This paper presents a low-cost ultra-wideband (UWB) pulse generator that can vary the pulse duration digitally by using a step recovery diode (SRD), microstrip transmission lines and PIN diodes. First, a sharp edge is generated by using a SRD. Through the use of transmission lines and the PIN diodes, a pulse is formed…