Analytic-numeric considerations for contactless reader modulation

Unlike in conventional Wireless Communication, Contactless Communication technologies like Near Field Communication (NFC), Proximity Card systems or RFID Labels operated at 13.56 MHz are very much impacted by signal distortion caused by de-tuning of resonant loop antennas. In fact, these effects define the near-field communication channel over just a few centimeters operating distance. To ensure interoperability, modulation signal specifications at the air interface provided in base standards must be strictly maintained. Consequently, accurate measurement methods are important and it is essential for system design to meet the specifications. This paper shows a method to consider reader modulation at the air interface of the contactless coupling channel. We apply this method on two scenarios: On the Proximity Coupling Device (PCD) test environment for Card testing, and on a real reader coupled to NFC Forum Listener 1.