Analysis Of Response Characteristic Of Antennas Excited By Electromagnetic Pulses Based On FDTD

With the rapid development of microelectronics technology, the miniaturization ofelectrical and electronic systems, especially the use of large scale integrated circuits inmilitary systems, makes electromagnetic compatibility and electromagnetic interferenceproblems get great attention. Electromagnetic pulse is a powerful energy field whichgenerated instantaneously; it can be generated by thunder, high-power microwave bombs,nuclear explosions and electromagnetic pulse bombs etc. Once high-power electromagneticenergy coupled from the front door entrance such as antenna or transmission lines, it willtransport to sensitive units along one or more coupling path, and cause serious damage toelectronic devices. In many numerical analysis methods, Finite Difference Time Domain(FDTD) due to the advantage of starting from Maxwell equation directly without any exportequation, simple, intuitive and easy to master, has access to a wide range of applications anddevelopment in various aspects of electromagnetic engineering.This paper, starting with theoretical analysis, first simulated and analyzed the timedomain and frequency domain characteristics of several typical electromagnetic pulse, thendescribed the basic principle of Finite Difference Time Domain, next deduced differencediscrete equations, and analyzed how to select time step and space step, especially focused onPerfectly Matched Layer absorbing boundary condition, the introduction of incident wave andthe method of Near-Far field transformation.Secondly, this paper caculated the far field of the dipole antenna using the thin wireFDTD algorithm which is one of the meshing technologies. By compared with CSTsimulation results, the reliability of this algorithm was verified. Then the transient responsecharacteristics of the dipole antenna was caculated when ultra-wideband (UWB)electromagnetic pulse, high-altitude nuclear electromagnetic pulse (HEMP), high powermicrowave (HPM) illuminating. Moreover the current of the dipole antenna’s center, far fieldresponse and spectrum were caculated when the electromagnetic pulse illuminating indifferent angles.Finally, this paper caculated and analyzed how E plane horn antenna respond whenUWB electromagnetic pulse, HEMP, and HPM illuminating. The horn antenna’s far-fieldresponse is also calculated through transient near-far field transformation, and responsespectrum is obtained by using Fourier transform. At the same time, this paper analyzed how E plane horn antenna responds when these electromagnetic pulses illuminating in differentangles or different parameters of the same pulse, the caculation results have important valuefor assessing the electromagnetic damage of the equipments which connected to antenna andstudying the protection of electronic equipment and electronic systems.