A performance evaluation method for EMI sheet of metal mountable HF RFID tag

This paper proposes a performance evaluation method for Electromagnetic Interference (EMI) sheet of metal mountable RF identification (RFID) tag. The method is based on impedance matching principle, featuring several advantages such as non-contact, high sensitivity and simple configuration. A wireless power transfer model was used to analyze the measurement result, which was later on validated by numerical optimization method. In order to further characterize the performance of the metal tag in terms of the reading range, the relationship between the power transmission coefficient and the reading range is explored. By using the method, an EMI sheet prototype with precise resonant frequency was fabricated, demonstrating a greater read range over the commercial one.