Numerical Study of Electromagnetic Waves With Sources, Observer, and Scattering Objects in Motion

The finite-difference time-domain (FDTD) technique is applied for studying electromagnetic waves in the presence of different structures in motion: plane wave source (with low or high impedance), observation point, reflective plane surface, line source, and conducting wire illuminated by a plane wave. The movements are performed by changing the positions of the objects in the algorithm’s time loop. The computational aspects of the proposed method are analyzed rigorously. The curve-fitted results are compared with the results predicted by special relativity (references). Some aspects of special relativity are present in the direct FDTD approach, such as the independence of the velocity of electromagnetic wave propagation with the speed of the source and Lorentz local time (with a different physical interpretation). A technique is proposed for implementing relativistic Doppler effects. Also, it is shown that the amplitude of the electric field for a moving plane wave source does not increase with the speed of motion, if the impedance of the source is small. Moreover, for a moving scattering conducting wire, a phenomenon similar to shock waves can be observed. Finally, problems with accelerating or vibrating electromagnetic reflecting surfaces (RS) are investigated. The proposed method is suitable for a wide range of applications.