RFID IC Research Articles

Compact Meandered Folded-Dipole RFID Tag Antenna for Dual Band Operation in UHF Range

A meandered tag antenna is proposed for dual band operation in UHF (Ultra High Frequency) range at f1 = 866 MHz and f2 = 912 MHz. Initially, the proposed tag consists of folded dipole configuration with extended meandered arms to achieve single resonating band. The inverted L-shaped stub is embedded at the lower arm of the folded dipole to introduce additional resonance and realize the dual band operation at desired resonant frequencies. The proposed tag’s impedance is optimised to match conjugately to the RFID IC (Alien Higgs-4). The proposed dual-band tag is designed and simulated using CST microwave studio. The tag prototype is fabricated and is experimentally characterised to verify its impedance matching with respect to the employed RFID IC. The read range performance of the fabricated tag prototype is measured experimentally by placing the proposed tag on different type of objects like wood, fibre, plastic etc. validating its environment tolerance capability. The proposed tag is found to perform well in all the presented scenarios. The proposed tag is compact with volumetric size of dimensions 1920 mm3 and exhibits measured read range of 5.5 m and 5.8 m at 866 MHz and 912 MHz.

A Battery-Free Temperature Sensor With Liquid Crystal Elastomer Switching Between RFID Chips

In this research, we have developed a novel temperature sensor to be utilized in the Cold-Supply-Chain (CSC) for perishable items. This sensor conveys temperature threshold crossings by switching operation between two individual RFID ICs, i.e., two individual Electronic Product Codes (EPCs). The advantage of this sensor compared to other existing technologies is that it can operate passively (i.e., battery-free) through multiple room-to-cold and cold-to-room temperature cycles, in real-time, without requiring any form of resetting. This design utilizes innovative cold-responsive liquid crystal elastomers (LCEs), which change shape when stimulated by cold temperatures and returns to a relaxed state when the stimulus is removed. In fact, this is the first temperature sensor that conveys temperature threshold crossings by switching between two RFID ICs using LCEs. The correct operation of the sensor is validated by RFID measurements. ANSYS HFSS and ANSYS Circuit Designer were used for the simulation analysis. The performance of the proposed design was validated using simulations and measurements.

Functional and Consumption Analysis of Integrated Circuits Supplied by Inductive Power Transfer by Powering Modulation and Lock-In Infrared Imaging

The functionality and consumption of a Radio Frequency IDentification Integrated Circuit (RFID IC) supplied by inductive power transfer has been noninvasively analyzed. This has been done by means of an InfraRed Lock-In Thermography (IR-LIT) system and frequency modulating the RFID IC powering scheme by biasing the external powering coil considering several amplitude modulation waveforms. This generates thermal harmonics at the beating frequency in all IC blocks, enabling their detection as heat sources by IR-LIT. The main aspects addressed in this investigation have been the following: the suitability study of the proposed modulation strategies, the characterization of the coupling between coils and its effects on the RFID blocks, the RFID IC functional analysis, and the dependence of the local energy consumption on the total power delivered to the die. In addition, it has been determined that the RFID IC presents a dysfunction due to the deactivation of some blocks during operation. Results suggest that this unexpected behavior is due to a desynchronization between some of the RFID blocks. Consequently, this stops the internal control signal, deactivates some specific RFID blocks, and ceases the back-telemetry block operation.

Efficient Parametric Characterization of the Dynamic Performance of an RFID IC

In this letter, a measurement technique for a complete parametric characterization of the input impedance of an RFID IC is presented. The use of an SPDT switch to modulate the signal from the network analyzer provides the capability to measure the RFID IC activation level and its input impedance simultaneously. This data can then be used to fully predict the dynamic response and performance of an RFID tag.

Effect of Lossy Dielectric Overlays on the Read-Range of UHF RFID Tags

The effect of a lossy overlay on the read-range of UHF RFID tags is studied. The design of the tag antenna is optimized for long read-ranges and then the effects of a lossy overlay (cover) on its properties are studied. The tags are simulated with and without the lossy overlay material. The input impedance of tag antenna, power transmission coefficient and read-range are calculated and compared for the two cases of with and without overlay. Further, optimization of tag with lossy dielectric overlay is carried out. It is observed that even with the overlay of a lossy dielectric, read-range up to 9 m can be obtained by properly matching the antenna with the RFID IC.

A flexible surface wetness sensor using a RFID technique

This paper presents a flexible wetness sensor whose detection signal, converted to a binary code, is transmitted through radio-frequency (RF) waves from a radio-frequency identification integrated circuit (RFID IC) to a remote reader. The flexible sensor, with a fixed operating frequency of 13.56 MHz, contains a RFID IC and a sensor circuit that is fabricated on a flexible printed circuit board (FPCB) using a Micro-Electro-Mechanical-System (MEMS) process. The sensor circuit contains a comb-shaped sensing area surrounded by an octagonal antenna with a width of 2.7 cm. The binary code transmitted from the RFIC to the reader changes if the surface conditions of the detector surface changes from dry to wet. This variation in the binary code can be observed on a digital oscilloscope connected to the reader.

A 2.4‐GHz dual‐patch RFID tag antenna scattering analysis

AbstractA dielectric‐filled metal‐patch antenna combinable with an internal RFID IC chip is introduced. This antenna is designed to operate either in an empty space or on top of large metal surface. The proposed tag antenna's dimension is adjusted to produce the maximum amount of scattered power due to tag's internal‐impedance modulation for the normal incidence angle. A 2.44‐GHz dual‐patch antenna is fabricated to demonstrate the amounts of impedance‐modulated scattered power at various reader‐to‐tag angles depending on the tag antenna radiation pattern. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2241–2244, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21931

廃棄物の不法投棄・不適正処理防止のための支援システムの構築とその実証研究(環境工学)

In this study, the checklists for attestation against the waste conveyance/disposal contractors were made. And the prior notification system for movement of waste using RFID IC tag was constructed. This system is composed of the IC tag put up to waste, the cellular phone, the reader/writer, GPS installed in the vehicle and the information management center. Through the field survey and the empirical study, their possibility and some problems that should be examined were cleared.