Control of resonant bandwidth in frequency-selective surfaces by tilting the periodic elements

The work presented in this letter shows the effects of tilting the periodic elements in a frequency-selective surface (FSS). The intent is to show the existence of another degree of freedom that can be used in designing FSS. The analysis is done using the periodic Green's function as the kernel to an integral equation, which is solved using the method of moments. The example presented in this letter is that of an FSS composed of thin dipoles. It is shown that tilting the dipoles causes a slight shift in the resonant frequency as well as a reduction of the bandwidth. An empirical formula for the bandwidth as a function of the tilt angle is given. Another effect of the tilt is to allow the excitation of an additional resonance. This might or might not be desirable, depending on the application.