Printed antennas: from theory to praxis, challenges and applications

Miniaturized, highly integrated wireless communication systems are used in many fields like logistics and mobile communications. Often multiple antenna structures are integrated in a single product. To achieve such a high level of integration the antenna structures are manufactured e.g. from flexible boards or via LDS (laser direct structuring) which allows the production of complex monopole or dipole antennas with three-dimensionally curved shapes. Main drawbacks are the sophisticated production process steps and their costs. The additive deposition of metallic inks or pastes by a printing process is an alternative manufacturing method with reduced cost. <br><br> To implement such printed antennas we investigated in the fields of antenna design, simulation, printing technology and characterization. The chosen example of use was a customized dipole antenna for a Radio Frequency Identification application. The results prove the intended functionality of the printed dipole in regard to a highly cost efficient printing manufacturing

A quarter-wave Y-shaped patch antenna with two unequal arms for wideband Ultra High Frequency Radio-frequency identification (UHF RFID) operations

The radio-frequency identification (RFID) system which has become pervasive in the auto identification technology has been noticed to have several limitations. These limitations can be broadly divided into two major areas namely; application specific problems and general RFID problems. Application specific problems are common to the environment in which RFID tags are deployed such as metal, aqueous and irradiation environments. Whilst, the general problem of RFID tags include low gain, regional specifications and so on. In this paper, a new antenna prototype has been design and stimulated. The proposed antenna showed tendency of exhibiting improved gain from the previous RFID UHF antenna which is 0-1 dBi to -3 dBi and impedance bandwidth of 140 MHz. The proposed antenna is Y shaped patch with unequal monopole arms which are responsible for the different frequencies that the antenna operates and a quarter wavelengths was adopted rather than the popular half wavelength for size reduction. The fractional return-loss bandwidth for S11<10 dB and radiation efficiency are about 95% was obtained

Advanced Radio Frequency Identification Design and Applications

Radio Frequency Identification (RFID) is a modern wireless data transmission and reception technique for applications including automatic identification, asset tracking and security surveillance. This book focuses on the advances in RFID tag antenna and ASIC design, novel chipless RFID tag design, security protocol enhancements along with some novel applications of RFID

Wireless sensor system for infrastructure health monitoring

In this thesis, radio frequency identification (RFID)-based wireless sensor system for infrastructure health monitoring (IHM) is designed and developed. It includes mountable semi-passive tag antenna integrated sensors capable of measuring critical responses of infrastructure such as dynamic acceleration and strain. Furthermore, the system is capable of measuring structural displacement. One of the most important parts of this system is the relatively small, tunable, construction material mountable RFID tag antenna. The tag antenna is electronically integrated with the sensors. Leading to the process of developing tag antenna integrated sensors having satisfactory wireless performance (sensitivity and read range) when mounted on concrete and metal structural members, the electromagnetic performance of the tag antenna is analyzed and optimized using both numerical and experimental procedures. Subsequently, it is shown that both the simulation and the experimental measurement results are in good agreement. The semi-passive RFID-based system is implemented in a wireless IHM system with multiple sensor points to measure dynamic acceleration and strain. The developed system can determine the natural frequencies of infrastructure and identify any state changes of infrastructure by measuring natural frequency shifts. Enhancement of the spectral bandwidth of the system has been performed under the constraints of the RFID hardware. The influence of the orientation and shape of the structural members on wireless power flow in the vicinity of those members is also investigated with the RFID reader-tag antenna system in both simulation and experiments. The antenna system simulations with a full-scale structural member have shown that both the orientation and the shape of the structural member influence the wireless power flow towards and in the vicinity of the member, respectively. The measurement results of the conducted laboratory experiments using the RFID antenna system in passive mode have shown good agreement with simulation results. Furthermore, the system’s ability to measure structural displacement is also investigated by conducting phase angle of arrival measurements. It is shown that the system in its passive mode is capable of measuring small structural displacements within a short wireless distance. The benchmarking of the developed system with independent, commercial, wired and wireless measurement systems has confirmed the ability of the RFID-based system to measure dynamic acceleration and strain. Furthermore, it has confirmed the system’s ability to determine the natural frequency of an infrastructure accurately. Therefore, the developed system with wireless sensors that do not consume battery power in data transmission and with the capability of dynamic response measurement is highly applicable in IHM

RFID-based Positioning System in Complex Environments

For effective identification of objects, Radio Frequency Identification (RFID) is  used in miscellaneous activities. In recent times, RFID is also used for positioning purposes. We show a scenario of wireless propagation  in free space observed by  up to  eight antennas with different polarization located in different positions. In this way, the polarization and diagram radiation of the antennas will play  a  significant role  in  producing  electromagnetic  field  in  the  region.   In  the second  case,  the  effects  of  disturbances  in  form  of  metallic  boxes  are  studied. The determination of the position is carried out by fingerprinting procedure

Design and performance of a flexible metal mountable UHF RFID tag

The large number of requirements and opportunities for automatic identification in manufacturing domains such as automotive and electronics has accelerated the demand for item-level tracking using Radio Frequency IDentification technology (RFID). End-users are interested in solutions that enable a range of objects to be identified without changing the structure of the objects. Designing an RFID tag, which can be mounted successfully on metallic objects and meets the end-user requirement is a major research challenge. The aim of the research outlined in this paper is to determine the effects of the harsh manufacturing environments in which RFID tags are used and compare the performance of a range of RFID tag substrates that can be used to isolate the RFID tag antenna from metallic objects. The goal is to determine which substrates allow RFID tags to operate efficiently when attached to metallic, lossy or dielectric objects whilst being low cost, high performance, flexible and in some cases reusable solutions. A flexible RFID tag with a substrate consisting of an elastomer / polymer has been investigated as a part of this research. Additionally, paper and PET substrates integrated with a number of different conductive inks, have also been investigated as potential optimal solutions for the high volume manufacture of UHF RFID tags suitable for metal objects. The research details the design and evaluation of performance of number of RFID tags when applied to tracking of automotive assets and components such as stillages throughout their manufacturing, assembly and the supply chain

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

Passive UHF RFID Tag for Airport Suitcase Tracking and Identification

A passive UHF tag configuration is presented for suitcase identification and tracking in airport handling applications. The proposed tag antenna solution is based on a conformal geometry, consisting of a folded dipole with orthogonal arms, appropriate for integration into the wall of injection moulded suitcases during its fabrication process. The tag antenna is designed for the ALIEN Higgs-2 integrated circuit. Simulated frequency dependence of the proposed UHF passive tag shows adequate performance across the world UHF RFID bands. Maximum tag detection range as well as detection isotropy were measured in several test environments both for a prototype tag attached to a suitcase and for a tag embedded in the suitcase wall. Full detection of the embedded tag was obtained for all suitcase orientations in the tested scenarios