Electric circuit modeling methods of electromagnetic shock wave in air for high power microwave propagation

Abstract

In recent years, as RF systems have been increasing rapidly, there is a growing need for studies about disturbance of electromagnetic shock wave propagation generated by high voltage pulse generator. Through frontdoor or back-door, electromagnetic shock wave can cause a upset or a lockup, that is, unsteady state in RF systems, and even cause a latchup or a burnout, which is permanent breakdown of the RF systems. Numerically, electromagnetic wave propagation can be analyzed by FDTD and FEM. However, it is difficult to calculate the entire high power microwave system using FDTD and FEM. Therefore, the purpose of this paper is to simulate the propagation of electromagnetic shock wave by using the electric circuit modeling methods without complicated calculations. In this paper, a concept of tapered transmission line is adopted as the electric circuit modeling methods. The tapered transmission line is used for impedance matching, and impedances of the tapered transmission line depend on the location. Because of its characteristic, the electromagnetic wave in the tapered transmission line is reflected and refracted while it is propagating. The electromagnetic shock wave propagation in air is expected by a reflection and a reflection coefficient in the tapered transmission line, and then we can simulate the electric circuit models with load by using EMTP (ElectroMagnetic Transient Program). We can describe the various electric circuit models of the electromagnetic shock wave in air. By using these models we can deduce the behavior of high power microwave propagation.