Adjustable circuit model of vircator according to its characteristics

Abstract

A virtual cathode oscillator (vircator) is one of the most important microwave generators, because it has advantages in simple structure, giga-watt level power and low impedance. Because of these advantages, it is widely used in high power electromagnetic (HPEM) pulse applications. The main disadvantage of the vircator is its low efficiency and it is complemented by simulation studies. Many of simulation studies are conducted by numerical method. Considering the connection to the pulse power part, a circuit modeling is needed. In this paper, the adjustable circuit model of the vircator according to its characteristics is proposed. Through the circuit model of the vircator, HPEM system can be handled as an integrated system, which contains a prime power part, a pulsed power part, a microwave source part, and others. This circuit analysis is simulated by the electromagnetic transient program (EMTP). Passive elements and switch are used to model for space-charge limitation, absorptions, oscillation and etc, which are derived from simulation condition (structure, input power). The vircator emission in the air is represented by the load. This study is helpful to efficiency researches because circuit elements are derived by the simulation conditions.