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.

Electromagnetic shielding for WLAN using modified-Hilbert fractals

Proposal of a fractal geometry with double similarity ratio for application in frequency selective surfaces with insensitive resonance frequency as a function of cell periodicity

In this paper a design for a broadband, light weight and low cost smart shield frequency selective device is proposed. The device consists of a dual layer printed circuit board patch array and is capable of absorbing WLAN signals in the frequency range around 5.5 GHz, whilst allowing almost unitary transmission outside this range, for example the GSM frequency band ranging from 0.8 to 2.1 GHz. Therefore it can effectively be utilized in telecommunications, radomes and as a shielding structure in electronic devices.

M. W. B Silva

Papers

Frequency selective smart shield design for wireless signals