Improving Communication Signal Transmission in Multiple Low-e Windows Using Frequency Selective Surfaces

The use of low-emissivity and solar control glass for thermal insulation in transportation and architecture poses a problem for communications, since the metallic coatings used in this glass attenuate radiofrequency (RF) signals. One solution to this problem is to define Frequency Selective Surfaces (FSS) on the coatings to ensure the transmission of RF signals while maintaining the thermal properties of the glazing. On windows with multiple coated panes, the interaction between the different surfaces grows more complex, as the dimensions of the structure are in the order of the wavelength of the signals involved. This is also an opportunity for the design of windows with specific transmission properties. The aim of this work is to present a design method for windows with multiple low-e coatings and multiple FSS based on the optimization of the RF transmission using an equivalent transmission line model. As a validation of our method, we show designs for windows with attenuation minima at 1, 1.8 and 5.8 GHz. Window samples according to these designs have been fabricated and measured, showing good correlation between simulation and experiment.