A novel method for wideband pulsed electromagnetic wave propagation characteristic analysis in layered medium

Abstract

Ultra wideband pulsed ground penetrating radar (GPR) detects buried object or underground medium characteristic by emitting and receiving pulsed electromagnetic waves. Establishing underground medium equivalent model and studying the electromagnetic wave propagation characteristic in media are very important to GPR data processing and underground object detecting. This paper introduces the actual pulse electromagnetic wave emitted by GPR as the wavelet, and presents a pulsed electromagnetic wave propagation characteristic analyzing method in layered medium. First, a underground equivalent layered medium model is established. Then the pulse electromagnetic wave emitted by GPR is decomposed into frequency components by Fourier-transform. For each frequency component, the reflected waves and the transmission waves from each interface of underground media are calculated respectively. Finally all of the reflection waves are transformed by Fourier-inverse-transform and recombined into the full GPR echo in time-domain. By using the GPR actual emitting wavelet to implement the propagation characteristic analyzing, we can precisely restore the echoes received by GPR. This method can also consider the electromagnetic wave dispersion and multiple reflections by frequency-domain analyzing approach. The time-domain echoes combining can effectively solve the electromagnetic wave coherence problem. Hence, the method mentioned in this paper have great advantages in studying GPR pulsed electromagnetic wave propagation characteristic in underground layered medium.