In the recent years, radio-frequency identification (RFID) technology has been widely integrated into modern society applications, ranging from barcode successor to retail supply chain, remote monitoring, detection and healthcare, for instance. In general, an RFID tag or transponder is composed of an antenna and an application-specific integrated circuit chip. In a passive UHF RFID system (which is the focus of presented research), the communication between the transponder tag and the reader is established by modulating the radar cross section (RCS) of the transponder tag. The need for flexible RFID tags has recently been increased enormously; particularly the RFID tags for the UHF band ensure the widest use but in the meantime face considerable challenges of cost, reliability and environmental friendliness.
The multidimensional focus of the aforementioned research encompasses the production of low-cost and reliable RFID tags. The state-of-the-art fabrication methods and materials for proposed antennas are evaluated in order to surmount the hurdles for realization of flexible green electronics. Moreover, this work addresses the new rising issues interrelated to the field of economic and eco-friendly tags comprising of paper substrate. Paper substrates offer numerous advantages for manufacturing RFID tags, not only is paper extensively available, and inexpensive; it is lightweight, recyclable and can be rolled or folded into 3D configurations.
The most important aspect of an RFID system's performance is the reading range. In this research several pivotal challenges for item-level tagging, are resolved by evolving novel structures of progressive meander line, quadrate bowtie and rounded corner bowtie antennas in order to maximize the reading distance with a prior selected microchip under the various constraints (such as limited antenna size, specific antenna impedance, radiation pattern requirements). This approach is rigorously evolved for the realization of innovative RFID tag antenna which has incorporated humidity sensor functionality along with calibration mechanism due to distinctiveness of its structural behavior which will be an optimal choice for future ubiquitous wireless sensor network (WSN) modules.
The RFID market has grown in a two-dimensional trend, one side constitutes standalone RFID systems. On the other side, more ultramodern approach is paving its way, in which RFID needs to be integrated with broad operational array of distinct applications for performing different functions including sensors, navigation, broadcasting, and personal communication, to mention a few. Using different antennas to include all communication bands is a straightforward approach, but at the same time, it leads to increase cost, weight, more surface area for installation, and above all electromagnetic compatibility issues. The indicated predicament is solved by realization of proposed single wideband planar spirals and sinuous antennas which covers several bands from 0.8-3.0GHz. These antennas exhibit exceptional performance throughout the operational range of significance, thus paving the way for developing eco-friendly multi-module RF industrial solutions.