Recently, Radio Frequency Identification (RFID) technology has become commonplace in many applications. It is based on storing and remotely retrieving the data embedded on the tags. The tag structure can be chipped or chipless. In chipped tags, an integrated IC attached to the antenna is biased by an onboard battery or interrogating signal. Compared to barcodes, the chipped tags are expensive because of the existence of the chip. That was why chipless RFID tags are demanded as a cheap candidate for chipped RFID tags and barcodes. As its name expresses, the geometry of the tag acts as both modulator and scatterer. As a modulator, it incorporates data into the received electric field launched from the reader antenna and reflects it back to the receiving antenna. The scattered signal from the tag is captured by the antenna and transferred to the reader for the detection process.
By employing the singularity expansion method (SEM) and the characteristic mode theory (CMT), a systematic design process is introduced by which the resonant and radiation characteristics of the tag are monitored in the pole diagram versus structural parameters. The antenna is another component of the system. Taking advantage of ultra-wideband (UWB) technology, it is possible to study the time and frequency domain characteristics of the antenna used in chipless RFID system. A new omni-directional antenna element useful in wideband and UWB systems is presented. Then, a new time-frequency technique, called short-time matrix pencil method (STMPM), is introduced as an efficient approach for analyzing various scattering mechanisms in chipless RFID tags. By studying the performance of STMPM in early-time and late-time responses of the scatterers, the detection process is improved in cases of multiple tags located close to each other. A space-time-frequency algorithm is introduced based on STMPM to detect, identify, and localize multiple multi-bit chipless RFID tags in the reader area. The proposed technique has applications in electromagnetic and acoustic-based detection of targets.
|Commitee:||Brown, Gary S., Davis, William A. Davis A., Kohler, Werner E., Reed, Jeffrey H.|
|School:||Virginia Polytechnic Institute and State University|
|School Location:||United States -- Virginia|
|Source:||DAI-B 79/01(E), Dissertation Abstracts International|
|Keywords:||Antenna, Chipless RFID, Detection, Scattering, Short-time matrix pencil method, Time-frequency analysis|
Copyright in each Dissertation and Thesis is retained by the author. All Rights Reserved
The supplemental file or files you are about to download were provided to ProQuest by the author as part of a
dissertation or thesis. The supplemental files are provided "AS IS" without warranty. ProQuest is not responsible for the
content, format or impact on the supplemental file(s) on our system. in some cases, the file type may be unknown or
may be a .exe file. We recommend caution as you open such files.
Copyright of the original materials contained in the supplemental file is retained by the author and your access to the
supplemental files is subject to the ProQuest Terms and Conditions of use.
Depending on the size of the file(s) you are downloading, the system may take some time to download them. Please be