Yvan Duroc

RFID Test Platform: Nonlinear Characterization

This paper presents a complete radio frequency identification (RFID) test platform to characterize the nonlinear effects produced by passive ultra-high frequency (UHF) RFID chips. In full operation mode, automated measurements of activation power, harmonic response level, and impedances are performed in a wide frequency range up to the fourth harmonic. The characterization method, platform composition, and operation are explained through real measurements on UHF Class-1 Generation-2 chips. A harmonic treatment is presented thanks to the joint use of an RFID tester and impedance tuners, and the effect of the antenna-chip impedance matching on the harmonic responses is compared before and after treatment. To the best of our knowledge, no similar platform has been presented in the literature.

Optimum integration of passive UHF RFID tag-rectenna in a single feed dual band antenna

In this paper, a design approach for the efficient integration of passive RFID tag operating at UHF 868 MHz for RFID communication and a rectifier operating at 2.45 GHz for energy harvesting application, both in a single feed dual band antenna is presented. Initially, the RFID chip and the rectifier element were characterized. Therefore, the step by step design process for the integration of each element is carried over, for a maximum power transfer to the passive RFID chip and the rectifying circuitry. The non-linear effects of rectifier and RFID chip are considered in an electric-electromagnetic co-simulation, ensuring the conditions at the threshold activation power at the RFID chip. 36.9 % RF-to-DC conversion efficiency is ensured at 2.45 GHz for -10 dBm input power. The sufficient isolation is provided at both frequencies to support an RFID communication and at the same time, harvesting from the 2.45 GHz band.

Performance optimization for the choice of impedances in the design of passive RFID tags

Nowadays, the RFID technology is implanted all over the world across various applications. The main improvements are often increasing the read range and reducing the power consumption. This paper presents a method to design a passive RFID tag considering the variations of the chips impedance and the power used by the reader. According to the desired performances, optimization could be done on read-range or consumption. An example, based on the literature, validates the analytical solution. The results show that, for a given set of parameters, the read-range can be improved from 6.8 m to 8.2 m at 865 MHz.

Multiple-Input Multiple-Output Antennas for Ultra Wideband Communications

La radio Ultra Large Bande (ULB) promet de nouveaux marches dans les domaines des reseaux personnels hauts debits et de capteurs. De sorte a ameliorer la robustesse du lien radio et le debit, l’association des techniques MIMO a l’ULB a ete envisagee. En vue d’une realisation pratique, un challenge fondamental reste la conception des antennes qui doivent repondre aux contraintes de l’ULB et des systemes multi-antennaires, et aux contraintes physiques et economiques. Dans ce contexte, plusieurs nouveaux designs d’antennes MIMO ULB sont proposes. Leur caracterisation s’appuie sur les parame��tres conventionnels utilises en conception d’antennes ainsi que des parametres specifiques a l’ULB et au MIMO. En particulier, un nouveau design compact presentant une forte isolation grâce a l’insertion d’un stub sur le plan de masse est propose. Une nouvelle methode de modelisation du couplage mutuel, qui presente l’avantage d’offrir de nouvelles approches pour le compenser, est egalement introduite.

A new concept of UHF RFID tag for metallic object tracking with embedded cavity

This paper presents a new solution for labeling metallic items like boxes and cavities. The proposed tag is based on the use of electromagnetic properties of cavities and the passive loop AKTAG RFID tag. Moreover the design avoids the physical connection between the RFID chip and the antenna. Simulation and measurement results are in good agreement. The feasibility of performing hidden tag using existing metallic cavity embedded in the object structure is demonstrated. When the tag is inside the cavity, a read-range of 5.5 m was measured in anechoic chamber, and a read-range of 7.7 m is reached when the loop tag is directly coupled to the slot.

Passive UHF RFID backscattering for indoor lighting control

This paper proposes the use of a passive RFID light sensor in a daylight-adaptive lighting system. In such a system, the dimming levels of light sources are adapted to changing daylight such that a desired illuminance distribution is achieved at the place. The system is composed by photo-sensible passive RFID tags used as light sensor nodes and RFID readers connected to a central controller. The use of the passive UHF RFID technology avoids the use of complex feedback light control algorithms as also simplify the deployment of the sensor network. Experimental results showed the proposed solution. The light variations can be sensed with high resolution having completely passive and wireless sensors.