Co-design of flip chip interconnection with anisotropic conductive adhesives and inkjet-printed circuits for paper-based RFID tags

In this paper we study the radio frequency performance of interconnect using anisotropic conductive film (ACF). A series of experiments are conducted in order to measure and model the electrical characteristics of inkjet-printed circuits on paper substrate as well as the impedance parameters of ACF interconnect at high frequency. Four-point measurement structure, time domain reflectometry (TDR), vector network analyzer (VNA) and de-embedded technology are used to ensure the accuracy of experiments. Equivalent circuit models are built based on the experimental results. Finally, these models are considered as parts of the matching network and circuit design for the RFID receiver, which can be co-designed for developing paper-based electronic systems. It is found that since the difference between RFID tags with and without ACF interconnects is negligible, the influence of ACF interconnects can be ignored for paper-based UHF RFID tag. ACF is a feasible interconnect material for paper-based RFID tags.