Characterization of Glass Samples for On-Glass WiFi and UHF RFID Antenna Design

In this paper, the measurement results of six different glass samples including relative dielectric constant and loss tangent are presented. The samples include three clear float glass sheets from different suppliers, extra clear float glass with low iron content, a blue-tinted and green tinted float glass. In order to prevent the effect of the glass to air interface, several layers of glass sheets are stacked together forming a sufficient sample volume that can accommodate most of the fringing electric fields from the open-end probe. The investigated frequency ranges from 10 MHz to 6 GHz. The measured data are then imported into an EM simulation tool to design UHF RFID reader and WiFi patch antennas with the center frequencies of 950 MHz and 2,450 MHz, respectively. The radiator is modeled using a copper layer with a thickness of 0.038mm corresponding to the thickness of commercially available adhesive copper tapes. Performances of the antenna on each glass substrate are compared. The results of the studies will be considered for the design of an on-glass antenna with a transparent radiator made of a transparent conductive film in future work.