TRI-BAND FREQUENCY-SELECTIVE SURFACE WITH CIRCULAR RING ELEMENTS

Theoretical analysis, physical reasonings, and experimental verificati ons are presented for a frequency selective surface with circular ring elements. Both double-screen and single-screen designs are generated for a tri-band system that reflects the X-band signal while transmitti ng through the S- and Ku-band signals. In these designs, the dielectri c loading effect is used to reduce ring size and element spacing and t hus avoid the grating lobe problem. The circular ring element is very insensitive to a large variation of the RF incident angle.