Electromagnetic shielding for WLAN using modified-Hilbert fractals

A novel modified-design of Hilbert curve is presented, which has stable frequency response for both TE and TM polarizations. Furthermore, a frequency selective surface (FSS) based on this modified-Hilbert curve is proposed for shielding against dual-band WLAN. It has an insertion loss of more than 15 dB with the bandwidths of 220 MHz at 2.45 GHz and 160 MHz at 5.78 GHz. The proposed FSS provides an excellent stable performance for both TE and TM polarizations under the incident angles of 0° through 60°. In addition, the size of unit-cell is only 0.082λ
0
×0.082λ
0
, whereλ
0
represents the free-space wavelength.