Measurement of Inkjet-Printing Parameters for Accurate Chipless RFID Tag EM Simulation

The use of Chipless RFID tags has been increasing for many applications, especially for structural health monitoring (SHM) applications where they are either affixed or embedded in materials and structures. The practical utility of chipless RFID is dependent upon the ability to manufacture tags in a cost-effective manner. One approach for achieving this is through the use of an inkjet printer and conductive ink. However, in order to harness the benefits of printed tags, it is necessary to know the dielectric properties of the substrates on which the tags are printed, as well as the conductivity of the printed conductors (i.e., ink) so that the tags can be properly simulated using electromagnetic (EM) models. It is also necessary to understand the performance differences that occur when tags are manufactured via inkjet-printing vs. when they are manufactured as printed circuit boards (PCBs). This work presents the dielectric property measurement results for three different paper substrates commonly used in tag printing from X-band (8.2 – 26.5 GHz) to K-band (18 - 26.5 GHz). Additionally, conductivity measurement results for silver nano-particle inkjet-printed conductors are also reported. These dielectric property and conductivity parameters are then used in tag EM simulations, and in the future when they are applied for SHM applications. PCB and printed tags are manufactured and measured to compare their performance both to each other and to simulation results.