الفهرس 
Chapter 1: IntroductionOnly 14 pages are availabe for public view
 |  | from | 138 |  |  |
| | | from | 138 | | |
Abstract
This thesis addresses the design and implementation of a chipless RFID system. The system main components are; Tags, Readers and a control software. The research work in this thesis focus on both readers and tags designs. The reader is based on the use of USRP N210 transceiver platform to transmit, receive and analyze the received signal after getting the required data from tag. The reader antenna is chosen to be a dual polarized horn antenna. The main focus in this thesis is to reach the optimum tag design that has a compact size and at the same time has a large response to the reader signals. The thesis investigates different approaches to design the RFID resonators; coupled line resonators, open stub resonators and metamaterial resonators. The tag in all cases has two orthogonal antennas connected via a set of resonators based on the aforementioned design approaches. The orthogonality of the two antennas has the benefit of receiving a wave with a certain polarization and then after passing the signal via the resonators where their performance indicate the tag bits level, the tag retransmit the modified signal with a new polarization that is orthogonal to the received one. This facilitates the separation between the received signal and the retransmitted signal that carry the tag information. Thus, one can understand that the tag is energized by the received signal so, it could be classified under the passive RFID tags category. The tag compact size stems from the use of a fractal shaped antenna that has small size compared to the commonly used monopole antenna in conjunction with the resonator compact approaches. The proposed tags are effectively implemented using low-cost substrate materials which in turn reduce the overall cost. The chipless tag uses the amplitude of the spectral signature of a multiresonator circuit and provides 1:1 correspondence of data bits. In addition to the miniaturization approach of both the antenna and the resonators, two novel concepts for further miniaturize the tags are introduced. The first concept is to build a double layer tag with four orthogonal antennas without affecting the radiation of each other. The second concept is the use of a novel coding technique that enhance the tag bit bearing capacity. Experimental results reveals a good agreement between the simulation and experimental results.