Addressing the Effects of UHF RFID Tag Crumpling

Modern designs for RFID tags are often built on flexible substrates to ensure a wide scope of applications. However, the tag design often neglects the effect of mechanical substrate deformation, and typically considers flat surfaces only. We demonstrate how bending or crumpling of a tag can affect its performance by e.g. shifting the resonant frequency or its impedance matching. This is achieved by analyzing the most common and fundamental devices, namely a resonant antenna (a patch) and a transmission line (a microstrip), in a simulation environment which allows for arbitrary mechanical deformation. This goes beyond the current state of the art, which typically considers only simple bending, and enables performance predictions for truly flexible and even crumpled RF-electronics.