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

Tattoo Antenna Temporary Transfers Operating On-Skin (TATTOOS)

This paper discusses the development of RFID logo antennas based on the logos of Loughborough University and the University of Kent which can be tattooed directly onto the skin’s surface. Hence, this paper uses aesthetic principles to create functional wearable technology. Simulations of possible designs for the tattoo tags have been carried out to optimize their performance. Prototypes of the tag designs were fabricated and read range measurements with the transfer tattoos on a volunteers arm were carried out to test the performance. Measured Read ranges of approximately 0.5 m have been achieved with the antenna 10 µm from the body

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

Evaluation of antenna design and energy harvesting system of passive tag in UHF RFID applications

Backscattering communication-based Radio Frequency Identification (RFID) has been essential to the rapid advancement of IoT devices. However, most RFID applications only utilize relatively simple antenna designs. This work contributes in two ways: we investigate the impact of different antenna configurations on a passive network using backscattering technology. In addition, we evaluate the designs of power harvesting technologies valid for Ultra-High-Frequency (UHF) RFID applications. Our evaluations demonstrate that tailored antenna designs can more efficiently achieve application requirements when compared to a simple universal antenna. In addition, we give recommendations on energy harvesters for applications operating in different scenarios

UHF RFID tag implementation on cork substrate for wine bottle monitoring

Wine industry is starting to deploy RFID technology for production control, logistics or innovative marketing. However, identifying wine bottles is difficult due to the unfavorable material content for the operation of the antennas. The thesis consists on the implementation of a UHF RFID tag placed on cork substrate in order to provide a feasible way of identifying wine packaged bottle. The proposed RFID tag consists on a meandered line dipole antenna, designed to be conformed so that it can be adapted to the shape of the cor

Optimum Performance of UHF RFID Tags in Dielectric Environment

Ultra High Frequency Radio Frequency Identification (UHF RFID) technology has gained prominence in recent years. It is being deployed extensively in supply chain and asset tracking by retailers to better control their inventory. The main drawback of UHF RFID tag antenna is that it is sensitive to the environment in which it operates. The performance of the tag degrades when placed on conductive or dielectric objects. While RFID tags near metal have been extensively evaluated in the literature, tags on and in dielectric media have received less scrutiny and rigorous evaluation. In this thesis, we develop a rigorous theoretical model for the behavior of RFID tags immersed in a dielectric medium using the Uda model and embedded T-match antenna. From this, we are able to investigate a number of criteria for optimality. We find that the simplest optimality condition is not physically realizable, and more realizable models yield several results that are of practical interest. Also, we propose a method to determine the input impedance of a center-fed dipole using a five element equivalent circuit. We relax the conditions for optimality and do an exhaustive search for the optimal design over the parametric space. Finally, we validate the model and present the trade-off to be made with the power transfer efficiency to obtain a tag working in wider range of dielectric materials. We make two specific recommendations for future work to increase the accuracy and usefulness of this work

Novel Passive RFID Temperature Sensors Using Liquid Crystal Elastomers

When transporting perishable foods in the Cold Supply Chain (CSC), it is essential that they are maintained in a controlled temperature environment (typically from -1° to 10°C) to minimize spoilage. Fresh-food products, such as, meats, fruits, and vegetables, experience discoloration and loss of nutrients when exposed to high-temperatures. Also, medicines, such as, insulin and vaccines, can lose potency if they are not maintained at the appropriate temperatures. Consequently, the CSC is critical to the growth of global trade and to the worldwide availability of food and health supplies; especially, when considering that the retail food market consists mostly (approximately 65%) of fresh-food products. The current method of temperature monitoring in the CSC is limited to discrete location-based measurements. Subsequently, this data is used to assess the overall quality of transported goods. As a result, this method cannot capture all the common irregularities that can occur during the delivery cycle. Therefore, an effective sensor solution to monitor such items is necessary. Radio Frequency Identification (RFID) is a pragmatic wireless technology with a standardized communication protocol. Thus far, passive RFID temperature sensors have been investigated. However, each design has a limitation from which a set of design guidelines for an improved sensor solution is developed. That is, the new sensor should: (a) be compact to be applicable on individual products, (b) utilize purely passive technology to ensure longevity and cost-effectiveness, (c) monitor goods in a continuous fashion (e.g., operate through multiple room-to-cold and cold-to-room temperature cycles), and (d) operate in an independent mode, so that no resetting is required. In this research, antenna systems and RF circuit design techniques are combined with Liquid Crystal Elastomers (LCEs) to develop three novel temperature sensors. LCEs are temperature responsive polymers that are programmable and reversible. Notably, LCEs return to their original state when the stimulus is removed. Also, for the first time, cold-responsive LCEs are incorporated into the designs presented in this research. Two of the developed sensors convey temperature changes through the controlled shift in the operating frequency. The third design conveys temperature threshold crossings by reversibly switching operation between two RFID ICs (or two Electronic Product Codes). Finally, all designs have been fabricated and tested with favorable results in accordance to the above mentioned guidelines