3D FDTD Forward Of Rectangle Loop Transient Electromagnetic

Now, rectangular loop is widely used as exciting device when we detect different objects with transient electromagnetic method (referred to as TEM).It is noteworthy that data interpretation still stays on one-dimensional because of comparatively little investigation.3-dimensional response of TEM similar to actual situation mostly, so study on3-dimensional numerical simulation has important significance for improving its application level and interpretation accuracy. In this paper, we realized3-dimensional forward of transient electromagnetic field excited by rectangular loop with Finite-difference Time-domain Method. Main works are abstracted as follows:(1)Firstly, we deduced the expressions of frequency domain field excited by rectangular loop in terms of loop area integral for magnetic moment based on frequency domain field excited by vertical magnetic dipole.And then, we obtained expressions of response to the magnetite according to G-S algorithm.(2)This paper especially expounds control equations, spatial discretization, time discretization, initial time and boundary conditions. Furthermore, we deduced3-dimensional iterative equations of explicit finite difference.(3)Based on calculation of induction electromotive force at geometric center for homogeneous half-space, H-type model and K-type model, we calculated accuracy of FDTD and the effects of time interval and space interval on the numerical solution of the model are discussed.(4)By comparing all-time carve feature of homogeneous half-space and Lowe resistance plate, By comparing contour map of homogeneous half-space and Lowe resistance plate at20time-points, physical explanation was given for which TEM detect low resistance body sensitively:In homogeneous half-space, isoline radiated by electromagnetic field can be regarded as a sphere in advanced stage. But for Lowe resistance plate, once electromagnetic field spread to low-resistant anomalous bodies, the Negative Extreme-value will stay in the its surrounding for a long time.