Exploring the Meta-Surface for Broadband TE1,1-mode in Circular Window

The plane surface of a dielectric disk window is engineered in three different patterns to explore the possibility of widening the frequency bandwidth. The reference bandwidth is taken as that for plane disk window considered in two thicknesses. The material chosen for window is Teflon. The mode and frequency range, for which window is examined, are respectively TE
1,1
and 20–60 GHz. The window bandwidths of 12.38 GHz (32.93%), 16.74 GHz (36.2%) and 21.18 GHz (45.06%) are obtained, respectively, for rectangular, circular and triangular tip bars for the circular TE
1,1
mode at 20dB return loss. However, the bandwidth of plane disk window without surface modification is 2.65 GHz (5.68%).