Numerical confirmation of scattering anomalies observed in FSS applications

In this paper a special kind of transmission anomalies of freestanding freq uency selective surfaces (FSS), characterized by a sharp breakdown in the p assband. is presented. First revealed by measurements, they could now be co nfirmed by numerical simulations based on the Method of Moments combined wi th the Floquet theorem. The paper presents the dependence of such anomalies on the variations of physical parameters like frequency, angle and polariz ation of the incident wave. Furthermore we have investigated the influence or the structure and grid ge ometry by varying the unit cell dimension and the structure periodicity. Su bsequently we present the magnetic and electric current distribution at sig nificant frequencies to get a further insight into the physical nature of t he phenomenon. Numerical results for several FSS configurations are compare d with measured values.