Scale Changing Technique for the Electromagnetic Modeling of Planar Self-Similar Structures

A scale changing approach is proposed for analyzing the electromagnetic scattering from discrete self-similar (e.g., log-periodic or pre-fractal) planar structures. Such structures present metallic patterns at multiple scale levels and are viewed here as the superposition of multiple domains enclosed with appropriate boundary conditions. In each domain higher-order modes provide the accurate local description of the electromagnetic fields while lower-order modes are used to model the electromagnetic coupling between the various domains at large scales. The scale changing technique is applied here to the electromagnetic modeling of multifrequency selective surfaces and discrete self-similar (pre-fractal) scatterers. Experimental data are given for validation purpose. It is seen that the proposed technique is much better than the method of moments in time costing.