Wearable RFID Tag on Denim Substrate for Indoor Localization Applications

This work presents the implementation of a wearable antenna designed and realized in fully textile materials and integrated in a RFID (Radio-Frequency IDentification) tag for indoor localization functions. Starting from the results obtained with a tag operating at 2.4 GHz realized with classic antenna substrates, in this research denim has been chosen as substrate and a thin film of adhesive copper has been stitched on it, in order to configure the final layout of the patch antenna and its ground, whereas the feeding circuitry of the tag is placed on a flexible Kapton layer and can be attached on a velcro strip in order to be removable if the clothes need to be washed. The suitable denim thickness and different bending situations have been tested in a real indoor scenario with a custom reader exploiting the radar monopulse principle, in order to reach the best localization accuracy.