Reduction of Power-Discretization Effects in UHF RFID Tag Performance Estimation Systems based on Off-The-Shelf Programmable Readers

The rigorous electromagnetic characterization of passive UHF radio-frequency identification (RFID) tags is a challenging task. Among various solutions, in a previous work an automatic tool for the over-The-Air evaluation of significant RFID tag metrics has been presented. Once fixed the distance, the system, based on the estimation of the minimum power emitted by the interrogating reader capable to energize the tag under test, has an accuracy that, although adequate, is limited by the minimum power step at the reader side. In this work, a new platform implementing a smart method to overcome this limit while preserving flexibility and cost-effectiveness, is presented, implemented and tested. The platform can automatically vary with continuity the interrogating distance-which becomes hence a new degree of freedom-and it is able to estimate for each frequency the couple power-distance which annuls the estimation error due to the power-discretization.