Résumé
This paper presents a study on the coupling between a reader and a contactless object in order to define some good working rules to deal with objects with small antennas (NFC mobile phones, key fobs...). We will define a model representing the magnetically coupled system composed of the reader and the RFID object in order to introduce the coupling factor which is the key parameter. The coupling factor variation according to reading distance and antennas shapes is a must to predict the overall system performance.