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Micro Electro Mechanical Systems (MEMS) are systems based on a diversity of technologies whereby tiny mechanical elements with excellent system properties can be implemented. The substrate properties such as relative permittivity, relative permeability and electrical conductivity is varied and its effects on electric field distribution, displacement and potential is analyzed in MEMS EVA tunable filters...
A novel type of strong-coupling five-gap extended output cavity is investigated for the W-band SBEIK to verify its resonant advantages of mode separation, gap fields coupling and RF energy exporting etc. And the degeneracy mode competition for the strong-coupling five-gap cavity is studied due to its axial period structures. The result shows that the frequency interval between the work mode and vicinal...
The analytical expressions of the beam-wave coupling coefficients, the beam-loaded conductance and bunching current in the multi-gap coupled cavity are derived based on space-charge wave theory. Through calculating those expressions in a Ka-band three-gap coupled cavity for modes 2π, π and π/2 respectively, the mechanism of the beam-wave synchronization and coupling in the three-gap coupled cavity...
In this paper, design of the interaction circuit for a 95 GHz sheet-beam extended-interaction klystron (EIK) with uniform magnetic focusing is presented. Simulations with CST-3D PIC indicates peak RF output power of 10 kW is feasible with a 3.3 A, 19.5 kV beam. The beam shows good confinement without any beam interception.
A multi-beam monotron oscillator that has four-gap cavity and which is excited in-phase oscillation was numerically investigated. As a result of numerical calculations and optimization the capability obtaining in such device on a frequency 2450 MHz high electron efficiency (60%) was shown.
Indus-1 is 450 MeV / 150 mA synchrotron radiation source indigenously built at RRCAT, Indore, India. The RF system of Indus-1 consists of 31.613 MHz RF amplifier its associated LLRF (Low Level RF) control & RF cavity for compensation of synchrotron loss of the stored electron beam in storage ring. For proper operation ultra high vacuum is required in RF cavity. To achieve required gap voltage...
It is examined both analytically and numerically by using a two-dimensional electromagnetic solver the frequency tuning characteristics and electric-field patterns in split-cavity resonators suitable for π mode operation of monotrons. Consisting of two circular cavities coupled by a circular grid, such resonators exhibit unique features not found in hollow circular cavities, namely, the occurrence...
In this paper Eigen mode analysis has been carried out using Ansoft HFSS for high frequency 120 GHz, 140 GHz, 170 GHz, 503GHz and 1000 GHz gyrotron cavity. Eigen mode analysis has an idea about the excitation of the operating modes in the cavity of the gyrotron and obtained the simulated eigen frequency and field pattern of the modes. The CPU time on Pentium-4, 2.99 GHz system with 4 GB RAM was less...
A comparative study is given on electron bunching in transit-time tubes with uniform and stepped RF electric-field profiles. It is shown that the stepped profile provides a two-fold enhancement in the conversion efficiency in comparison with that obtained with a longitudinally uniform electric-field distribution. This improvement arises from a phase synchronization process due to the action of RF...
In this article, we report a reconfigure antenna that is able to radiate different topologies of radiation pattern. Such an antenna system is composed of a four-way power divider made from a cavity-type structure fabricated using printed circuit technology. Due to the symmetric electric field distribution in the resonant cavity, the power divider maintains equal amplitude- and phase- distribution...
The present report examines both analytically and numerically by using a two-dimensional electromagnetic solver the frequency tuning characteristics and electric-field patterns in a two-celled system consisting of cylindrical cavities coupled by a circular iris. It is shown that the presence of the iris introduces unique features not found in hollow circular cavities, namely, the occurrence of flat...
A comparative study is given on the bunching mechanisms which develops in transit-time tubes with RF-field bunching, often referred to as monotrons. Uniform and stepped wise longitudinal electric-field profiles are discussed, and it is shown that the two-fold enhancement in the conversion efficiency of a monotron operating in the ?? mode-instead of the longitudinally uniform TM010 mode for which the...
Surface roughness plays an important role in a cavity or slow wave structure. It may cause enhanced RF power absorption. It may lead to excessive local electric field enhancement that triggers RF breakdown. In a superconducting cavity, surface roughness may also cause local magnetic field enhancement that leads to abrupt quenching, i.e., rapid loss of superconductivity. In this work, we analytically...
The two-fold enhancement in the conversion efficiency of a monotron operating in the pi mode-instead of the TM010 mode for which the efficiency is limited to 20 percent-arises from a phase synchronization process due the action of RF electric fields of reversed signs in each partition of the bisected cavity.
In this work, we analytically compute the power absorption due to a hemispherical protrusion on a resonant cavity's surface. The permittivity, conductivity, and permeability of the protrusion may assume arbitrary values. The local field enhancement factors of both electric field and magnetic field on the protrusion are also calculated analytically. These calculations have been spot-checked against...
In this report the extensions of DEV 5.0 code including extended interaction multiple beam klystrons (EIMBK) simulation with identical and non-identical beams are presented. The features of the computational model are discussed.
In this paper, we present a novel ultra-fast material inspection system for continuously streaming dielectric materials, such as paper, plastic films, non-aqueous liquids etc. The material stream is being passed through a cavity resonator whose electrical parameters are altered by the presence of the material, due to its interaction with the electric field inside the resonator. The latter is employed...
A new RIB project, Beijing Radioactive Ion-beam Facility (BRIF), has been started at CIAE since 2004. In this project, a 100 MeV H- cyclotron, CYCIAE-100, is selected as the driving accelerator, providing 75-100 MeV, 200-500 muA proton beam. Multi-physics field simulation plays an important role in the design stage of this machine, which was investigated and presented in this paper. The work in this...
In this paper an independent tunable electron gun for a compact terahertz source based on free electron lasers is studied. In order to obtain a compact terahertz source, an electron gun played a dominant role. In this paper an independent tunable electron gun was designed and calculated. The gun was composed of two independent cavities. The feeding and the phase are independent, respectively. The...
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