Investigation of the Distribution Problem in the Operating State of an Electromagnetic Railgun: Radio Fuse Disturbance, Field Characteristics, and Susceptible

The purpose of this article is to analyze the front door coupling effect that may occur in the projectile receiver due to the discharge pulse radiation in electromagnetic railguns, and to simulate the discharge pulse interference. This phenomenon will have an impact on the launch of the projectile, causing its fuse to be disturbed, ultimately affecting the weapon performance of the electromagnetic railgun. Discharge refers to when the armature carrying the projectile is fired out of the chamber, and the armature connected between the two rails detaches, causing a circuit break in the electrical circuit during the operation of the electromagnetic railgun. The current flowing through the armature is disturbed, causing an instantaneous high voltage to penetrate the air gap between the two rails, generating nanosecond pulse width discharge voltage pulse radiation, with a spectrum of up to tens of megahertz. In this paper, we establish a receiving antenna model on the projectile, which is essentially a horn antenna, receiving electromagnetic pulses from the discharge process, and coupling the pulse interference through its front door. During the analysis and calculation, we established an antenna receiver model located in the C-band with a frequency of 6 GHz for simulation, analyzed and calculated the actual interference loaded on the projectile after front door coupling, and verified the correctness of the simulation settings and results by comparing with the literature. Finally, we found that because the main energy spectrum of the pulse is at MHz level, when the front door of the C-band horn antenna is coupled, the standing wave ratio of the antenna is very large and the gain is very small, so the pulse interference is filtered, which can make the interference finally loaded on the projectile insufficient to affect the normal operation of the projectile. At the same time, it is recommended to add an RF filter to the receiving channel to further enhance anti-interference ability, so as to ultimately enable the electromagnetic railgun to function properly.