Dual-Band RFID Tag Antenna Based on the Hilbert-Curve Fractal for HF and UHF Applications

A novel single-radiator card-type tag is proposed which is constructed using a series Hilbert-curve loop and matched stub for high frequency (HF)/ultra high frequency (UHF) dual-band radio frequency identification (RFID) positioning applications. This is achieved by merging the series Hilbert-curve for implementing the HF coil antenna, and square loop structure for implementing the UHF antenna to form a single RFID tag radiator. The RFID tag has directivity of 1.75 dBi at 25 MHz, 2.65 dBi at 785 MHz, 2.82 MHz at 835 MHz and 2.75 dBi at 925 MHz. The tag exhibits circular polarisation with -3 dB axial-ratio bandwidth of 14, 480, 605 and 455 MHz at 25, 785, 835 and 925 MHz, respectively. The radiation characteristics of the RFID tag is quasi-omnidirectional in its two orthogonal planes. Impedance matching circuits for the HF/UHF dual-band RFID tag are designed for optimal power transfer with the microchip. The resulting dual-band tag is highly compact in size and possesses good overall performance which makes it suitable for diverse applications

Antennas and Propagation of Implanted RFIDs for Pervasive Healthcare Applications

© 2010 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.This post-acceptance version of the paper is essentially complete, but may differ from the official copy of record, which can be found at the following web location (subscription required to access full paper): http://dx.doi.org/10.1109/JPROC.2010.205101

Communication system for a tooth-mounted RF sensor used for continuous monitoring of nutrient intake

In this Thesis, the communication system of a wearable device that monitors the user’s diet is studied. Based in a novel RF metamaterial-based mouth sensor, different decisions have to be made concerning the system’s technologies, such as the power source options for the device, the wireless technology used for communications and the method to obtain data from the sensor. These issues, along with other safety rules and regulations, are reviewed, as the first stage of development of the Food-Intake Monitoring projectOutgoin

Conformal Magnetic Composite RFID for Wearable RF and Bio-Monitoring Applications

©2008 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or distribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder.10.1109/TMTT.2008.2006810This paper introduces for the first time a novel flexible magnetic composite material for RF identification (RFID) and wearable RF antennas. First, one conformal RFID tag working at 480 MHz is designed and fabricated as a benchmarking prototype and the miniaturization concept is verified. Then, the impact of the material is thoroughly investigated using a hybrid method involving electromagnetic and statistical tools. Two separate statistical experiments are performed, one for the analysis of the impact of the relative permittivity and permeability of the proposed material and the other for the evaluation of the impact of the dielectric and magnetic loss on the antenna performance. Finally, the effect of the bending of the antenna is investigated, both on the S-parameters and on the radiation pattern. The successful implementation of the flexible magnetic composite material enables the significant miniaturization of RF passives and antennas in UHF frequency bands, especially when conformal modules that can be easily fine-tuned are required in critical biomedical and pharmaceutical applications

Antenna Design for Semi-Passive UHF RFID Transponder with Energy Harvester

A novel microstrip antenna which is dedicated to UHF semi-passive RFID transponders with an energy harvester is presented in this paper. The antenna structure designed and simulated by using Mentor Graphics HyperLynx 3D EM software is described in details. The modeling and simulation results along with comparison with experimental data are analyzed and concluded. The main goal of the project is the need to eliminate a traditional battery form the transponder structure. The energy harvesting block, which is used instead, converts ambient energy (electromagnetic energy of typical radio communication system) into electrical power for internal circuitry. The additional function (gathering extra energy) of the transponder antenna causes the necessity to create new designs in this scope

Compact Planar Antennas for Beam Steering and RFID Tags

The chapter presents innovative planar antennas for beam steering and radio frequency identification (RFID) applications. Beam steering has become vital in commercial wireless communications, including mobile satellite communications where high data rate communication is required. The chapter describes a low-cost beam-steering antenna based on a leaky-wave antenna structure that is capable of steering the main radiation beam of the antenna over a large range from −30° to +15°. Interest in RFID systems operating in the ultrahigh frequency (UHF) is rapidly growing as it offers benefits of long read range and low cost, which make it an excellent system for use in distribution and logistics systems. This chapter presents a technique of overcoming the limitations of conventional HF coils in RFID tags where the total length of the spiral antenna is restricted inside the available area of the tag

Definition, Characteristics and Determining Parameters of Antennas in Terms of Synthesizing the Interrogation Zone in RFID Systems

The radio frequency identification (RFID) systems are gaining in popularity in automated processes of object identification in various socioeconomic areas. However, despite the existing belief, there is no universal RFID system on the commercial market that could be used in all user applications. All components of a developed solution should be carefully selected or designed according to the specification of objects being recognized and characteristics of their environment. In order to determine parameters of propagation or inductively coupled system, especially when it is dedicated to uncommon applications, a multiaspect analysis has to be taken into consideration. Due to complexity, the problem is reduced to analytical or experimental determination of RFID system operation range and a “trial and error” method is mostly used in the industry practice. In order to cope with the barriers existing in the RFID technology, the authors give the review of latest achievements in this field. They focus on the definition, comprehensive characteristics and determination of the antenna parameters. They also pay attention to the 3D interrogation zone (IZ) that is the main parameter in which multitude technical aspects of the RFID systems are gathered simultaneously, as regards the theoretical synthesis as well as market needs

A Review Of Implementing Adc In Rfid Sensor

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The general considerations to design a sensor interface for passive RFID tags are discussed. This way, power and timing constraints imposed by ISO/IEC 15693 and ISO/IEC 14443 standards to HF RFID tags are explored. A generic multisensor interface is proposed and a survey analysis on the most suitable analog-to-digital converters for passive RFID sensing applications is reported. The most appropriate converter type and architecture are suggested. At the end, a specific sensor interface for carbon nanotube gas sensors is proposed and a brief discussion about its implemented circuits and preliminary results is made.Region Rhone-Alpes (France)CNPq (Brazil)INCT/NAMITEC (Brazil)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq