A Numerical Technique for Analyzing Electromagnetic Wave Scattering from Moving Surfaces in One and Two Dimensions

The electromagnetic wave scattering properties of a moving, perfectly conducting mirror are analyzed using a new numerical technique based on the finite-difference time domain (FD-TD) method. This numerical technique is unique in that it does not require a system transformation where the object is at rest but gives a solution to the problem directly in the laboratory frame. First, two canonical one-dimensional cases are considered, the uniformly moving and the uniformly vibrating mirror. Numerical results for the scattered field spectrum are compared to available analytical results, and an excellent agreement is demonstrated. The ability of the FD-TD model to obtain the physics of the double-Doppler effect (for the uniform translation case), and FM-like reflected spectrum (for the uniform vibration case) is highlighted. Second, the method is extended to two-dimensions where a plane wave at oblique incidence on an infinite vibrating mirror is considered. A good agreement with published results is demonstrated for this case. This new approach based on FD-TD provides a potentially strong tool to numerically model a variety of problems involving moving and vibrating scatterers where alternative analytical or numerical modeling means are not available.