Electrically thin and platform insensitive ultra high frequency radio frequency identification tags

The objective of this research is to design passive UHF RFID tags that are insensitive to the platform they are applied to. The tag antennas developed in this work will exhibit good read range in harsh electromagnetic environments, such as metallic objects, liquid containers and human skin, while balancing the tag unit cost and form factor with perfonnance. In the early part of this thesis a brief introduction to RFID, the essential antenna parameters, the physics of RFID and the environmental effects on tag antennas sets the background necessary for understanding the procedure used when designing and measuring tag performance. As part of this fundamental research process, a tag design methodology is developed and evaluated by designing a global tag, before proceeding to design passive tags specific for unfriendly electromagnetic environments. In later part of the thesis, passive platform tolerant tags will be designed to identify electromagnetically unfriendly objects in different real working environments. The first design will identify large EM unfriendly objects. The requirement for this tag is ruggedness and long read range on any object, while keeping the tag profile as low as possible. The second tag will be designed to identify curved metallic objects such as gas cylinder. This tag will be designed on a tou-gh flexible substrate to conformal on curved objects. This main objective of this design is to identify metallic cylinder from all direction in the plane of the tag antenna. The third tag will be an ultra-thin design for identification of objects where low profile and low cost platform tolerant tagging is required. Ultra low profile platform tolerant tag design is also one of the main objectives of this work, which will be achieved in this design. The last tag in this work will ~ designed to identify humans in secure environments, where temporary access to facilities or sites is paramount. This non-transferable tag will be designed to be mountable directly onto the skin surface in the form of a transfer patch in much the same way that a temporary tattoo could be applied. - Since passive tags have ·to be designed for massive production at low cost and high reliability, all the designs in this work will aim at uncomplicated planar structures with high efficiency and high manufacturing tolerance on low cost commonly available substrates .EThOS - Electronic Theses Online ServiceGBUnited Kingdo