Search

This article introduces an innovative methodology for measuring the impedance of RFID (Radio Frequency Identification) chips. The primary objective is to develop a technique that enables impedance measurement across a range of frequencies, centered around the critical operational frequency of RFID systems, specifically 13.56 MHz. Unlike conventional methods, which typically focus solely on the impedance at 13.56 MHz, this approach utilizes the reflection coefficient of the device under test (DUT) to measure impedance over a broader frequency spectrum. This spectrum encompasses the frequencies within the ISO14443 communication bandwidth. The excitation signal is carefully selected to closely mimic an actual RFID communication frame. The experimental results demonstrate the feasibility of this method by comparing the impedance measurements of passive component pairs against those obtained using a vector network analyzer (VNA). Subsequently, the technique is applied to an RFID chip, underscoring its practical applicability and accuracy. [ABSTRACT FROM AUTHOR]

This letter aims to study a multiantenna tag on a UHF RFID system. Impact of dual antenna on the read range is demonstrated. This letter shows that this enhancement is not only due to a better antenna gain, but also to the design of the backscattering system. Indeed, the backscattering modulator is connected on only one of the two inputs of the antenna. Measurements of prototypes designed in 0.18 CMOS process demonstrate that a tag with such a system stays visible for the reader around 2 m better than a one-antenna system. [ABSTRACT FROM PUBLISHER]