Effect of printing parameters on microwave performance of printed chipless RFID tags

The chipless Radio Frequency Identification system (RFID) will revolutionize the identification market due to its low-cost tagging methods. The printed version of the chipless tag is able to reduce the cost to few cents per tag. The microwave performance of the printed chipless tag is suffered due to the practical limitations of the overall fabrication procedure through printing. The bandwidth broadening is unavoidable for the printed tag, which directly hits on the data capacity. Similarly, the strength of the microwave signal is also degraded for printed RFID tag, which affects the reading distance of the tag. The fabrication of chipless RFID tag via printing involves several parameters such as the conductive ink processing condition, the substrate parameters and the geometrical dimension of the printed tag. We need to understand the relationship between these printing parameters with the microwave response of the printed tag, to analyze the key parameters affecting the response of the printed tag. A comprehensive experimental investigation is performed in this paper to evaluate the relationship between the printing parameters and microwave response of the printed tag. The printing parameters include conductive ink sintering type and sintering conditions and deposited ink thickness. A high-speed photonic sintering process is adopted for the first time to sinter chipless RFID tag so that chipless RFID tag can be manufactured using fast roll-to-roll printing process. Optimum conditions for the photon-sintering process are deduced through experimental analysis for conductive inks of various viscosity. The effect of the geometrical dimensions of the printed strip and the printing accuracy is also analyzed to understand the limitations of the printing technique in terms of tag size. The issues seen in the printed RFID tag, their reason and the solution is then deduced in the final section so that the printed chipless tag can accommodate the real world limitations to make viable commercial outcome.