Design and Characterization of Ink-Jet and Screen Printed HF RFID Antennas

The physical and electrical characterization of several patterns printed by ink-jet and screen printing are presented in this work. The main goal is to determine suitable techniques to manufacture RFID antennas by using different conductive Ag inks, pastes and substrates commonly used in RFID. The physical characterization consisted of measurements of the layer thickness and the RMS roughness of the patterns. DC electrical characterization has been carried out to study different conductive inks and substrates pointing out the lowest sheet resistance and the best printability for each analyzed case. Using the optimal conditions obtained from this work, coil inductors have been fabricated by both techniques in order to validate the present study. Ink-jet printed antennas have been fabricated with Sun Tronic Ag ink on PEI substrates and screen printed antennas have been fabricated on various substrates using screen mesh densities of 90h and 140h. Finally, a semi-passive RFID tag for the HF band providing temperature and humidity sensor capabilities is presented.