Vacuum Electronic Devices and Applications

This issue of Defence Science Journal (DSJ) contains a collection of nine manuscripts from National Symposium on Vacuum Electronic Devices and Applications (VEDA-2019). Vacuum Electronic Devices and Applications Society organises VEDA symposium/conference/workshop every year at different locations of India. VEDA has established itself as a leading platform for active and innovative research of microwave tubes. It provides a forum for knowledge sharing and exhibition of theoretical and technological development in the general areas of vacuum electronics devices and its system applications. It organises special session to enhance Research Institutes – Industries and Academia Interaction

Parametric Study of the Reltron Oscillators

In this paper, effect of the input DC electrical parameters, such as, pulse shape, cathode voltage and the postacceleration voltage on the performance of reltron oscillator have been investigated. For this purpose, a typical reltron oscillator has been designed and simulated. The mode of excitation, resonant frequency and electric field patterns in the RF modulation cavity of the reltron structure has been studied through electromagnetic simulation. The RF output performance and effect of DC electric pulse shape is studied through 3D PIC simulation. To get a practical insight of the excitation signal effect on the performance of device operation, various pulse shapes with different rise, hold and fall time have been studied the pulse of hold time 70 ns and rise and fall time of 5 ns gives maximum stable RF power. Device parametric analysis for the different cathode and post-acceleration voltages has also been investigated. With a beam current of 750 A, cathode voltage of 200 kV and post-acceleration voltage of 800 kV, the device provides ~350 MW with ~46% efficiency

Electromagnetic Analysis of the HPM Oscillator-Reltron

In this paper, electromagnetic analysis of the reltron, which is a compact, simple and efficient high power microwave (HPM) source has been presented. The beam wave interaction process of the reltron oscillator has been analyzed to understand the device physics. The split cavity oscillator and relativistic klystron principles have been extended to demonstrate the electric field responsible for beam bunching and the electron beam modulation process in the reltron. The analytical formulation to obtain the RF energy growth and efficiency of the device has also been presented. To validate the analytical results and to evaluate the overall performance of the device, beam present simulation of reltron has been performed using commercial 3D PIC simulation code "CST Particle Studio". With the parameters of a previously reported experimental reltron device, the present analytical calculation provided ~240 MW RF output power with ~38% efficiency while the PIC simulation provided RF output power of ~225 MW with ~36% efficiency at 2.75 GHz frequency. The obtained analytical and simulation results have also been found in agreement of ~6% with this experimental work