Two-Section Folded-Waveguide Slow-Wave Structure for Terahertz Extended Interaction Oscillator

Abstract

Extended interaction oscillator (EIO) is a promising terahertz (THz) power source, which has many potential important applications, such as military radar, medical imaging and material science research, and so on. To improve the operation performances of the THz EIO, a novel type of two-section folded waveguide (TSFW) slow wave structure (SWS) is proposed in this paper. The dispersion characteristics for TSFW obtained by an equivalent circuit model are analyzed, and the output characteristics for TSFW EIO are studied and optimized with the help of 3-D particle-in-cell simulation. Comparing with the single section of FW SWS, the remarkable enhancement of output power in the TSFW SWS is observed from 50 up to 130 W. Based on the proposal model, the TSFW is fabricated with a high speed numerical control milling machine and its transmission characteristics are tested. The results of the cold test are in agreement with theoretical predications. Index Terms-3-D particle-in-cell (PIC) simulation, extended interaction oscillator (EIO), terahertz (THz), two-section folded waveguide (TSFW) slow wave structure (SWS).

A nonlinear analysis of the terahertz serpentine waveguide traveling-wave amplifier

“…21 PIC simulations were carried out to predict and validate the nonlinear interaction model. The PIC simulation calculates the development of fields and particles through time at discrete time samples.…”

Design, fabrication and measurement of a novel 140 GHz folded waveguide based on SU-8 UV-LIGA technology

“…In order to improve the performance, Liu et al proposed a V-type folded waveguide SWS and Liu et al designed a folded waveguide SWS with a drift section. In order to realize micromachining with high precision, Tueck et al obtained a folded waveguide SWS by deep reactive ion etching (DRIE), and So et al fabricated a folded waveguide SWS by the LIGA technique [8][9][10][11].…”

Experimental demonstration of a terahertz extended interaction oscillator driven by a pseudospark-sourced sheet electron beam

“…[1][2] Vacuum electronic devices (VEDs) have been widely studied as promising THz radiation sources because of their high electronic efficiency, high power capacity and room-temperature operation. [2][3][4][5][6][7][8][9][10][11] When extending to THz frequencies, the radiation power of typical VEDs based on a thermionic cathode electron gun will be greatly reduced due to the small beam current that can be propagated down through a beam wave interaction structure of diameter typically on the order of the wavelength of operation. The limited beam current is mainly due to the restriction in the electron emission current density from thermionic emitters and the electron beam interception.…”

“…12 Firstly, to reduce the power loss in the interaction circuit, an extended interaction oscillator (EIO) was studied as its resonant slow wave structure (SWS) can be short in the order of only a few wavelengths long because of the high gain per unit length. [5][6][7] Secondly, to increase the beam current, a pseudospark-sourced sheet electron beam (PS-SEB) is employed to drive the resonant SWS. According to the experimental results of various pseudospark discharge systems, the PS-EB has much higher beam current density (>10 4 A/cm 2 ) than the beam generated by a thermionic cathode, and it can be confined by an ion-focusing channel generated by the system itself.…”