New graphic method design of wideband frequency selective surfaces embedded within dielectric layers

This paper extends the microwave impedance matching theory into wideband absorbing structure design. A straightforward graphic method is presented. An in-depth analysis was undertaken through lossy frequency selective surface embedded within dielectric layers. The effect of the surface resistance, size and element spacing of the square ring element and substrate characteristics on the input impedance of the absorber was further discussed by means of a circuital modeling prediction based on the Smith chart. The result was extensively verified by finite element analysis. The study shows that the graphic method is simple and practicable and using dielectric slab improved the absorbing performance at the lower frequencies.