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|Title: ||Novel RFID antennas for a modern library|
|Other Titles: ||Wei xian dai hua tu shu guan er she de xin ying she pin shi bie xi tong tian xian|
|Authors: ||Lau, Pui Yi (劉沛兒)|
|Department: ||Department of Electronic Engineering|
|Degree: ||Doctor of Philosophy|
|Issue Date: ||2010|
|Publisher: ||City University of Hong Kong|
|Subjects: ||Radio frequency identification systems.|
Libraries -- Inventory control.
Libraries -- Automation.
|Notes: ||CityU Call Number: Z699.75 .L38 2010|
x, 159 leaves : ill. 30 cm.
Thesis (Ph.D.)--City University of Hong Kong, 2010.
Includes bibliographical references.
|Abstract: ||This thesis presents a series of novel Radio Frequency Identification (RFID) reader
and tag antennas for a modern library. To be a modern library, an intelligent RFID
system is a key stone to achieve the goal. It includes many parts such as smart
bookshelves, multi-book borrowing and returning system, smart book sorting, security
gateway and tags for library resources. The performance of the antenna system is the
most critical element of any RFID installation. However, "one antenna fits all
concept can not be applied here. Instead of the conventional circularly polarized patch
antenna, specific designs are necessary for effective handling of smart bookshelves,
multi-book borrowing and returning system and multi-media resources. Consequently,
four different types of antennas are investigated including a directional beam tilted wire
antenna, a compact sequential rotated PIFAs array, a printed CP antenna with EBG
structure and a compact ring folded dipole tag antenna, for the UHF RFID library
Attention is first focused on design and investigation use of wire helix to achieve
directional beam tilted circular polarization (CP) for a multi-book check out and return
system. Unlike the conventional helical antenna, an accordion shaped monofilar axial
mode helix designed by curving the helix along the axis is investigated. This antenna is low profile as the 10-turn helix’s axial length is 0.354λ. It has an impedance
bandwidth (SWR<1.5) of 9% from frequency of 880MHz to 963MHz and the axial ratio
bandwidth (AR<3dB) of 6.5%. This antenna achieved a measured gain of 10.2 dBi
and tilted by 17° to the curving side.
In the second part, the idea of designing a low cost smart bookshelf antenna is
presented. A compact sequentially rotated printed inverted-F antenna (PIFAs) array
printed on a low cost material FR4 is investigated. In this design, the sequentially
rotated feeding technique is firstly introduced to top loaded PIFAs, to achieve a small
size, low profile, wide axial ratio bandwidth and a wide radiation beam. A numerical
analysis based on the method of moment is carried out to predict the characteristics of
the antenna. Different from the conventional sequential CP patch array, the proposed
design is small in size and offers a wide beam width of over 110°; it also preserves a
wide impedance bandwidth of 26.8% and axial ratio bandwidth of 11.6%.
In the following part, to further provide a low profile and low cost solution to
replace the conventional CP patch antenna for smart bookshelf and smart sorting system,
a printed CP patch antenna backed with a double-layer Electromagnetic band gap (EBG)
structure is proposed. The antenna is printed on 3 layers of low cost material FR4 with
thickness of 1.6mm (0.006λ). It achieves 80% thickness reduction by compared to the
conventional patch antenna but maintains the antenna gain of about 6dBi.
Finally, a compact ring tag antenna is specifically designed for multi-media
resources in the library. The antenna is modeled with the circular plastic CD.
Therefore, the impedance characteristic can be well conjugated matched with the Application Specific Integrated Circuit's (ASIC) and the read range can be maintained
even when tagged on multi-media resources. The ASIC Philips NXP EPC global Class
1 Generation2 RFID chip has a threshold power of -13dBm and chip-on-board
impedance is 16-j380Ω. The tag antenna is operated at the center frequency of
915MHz when placed on a 1.2mm thickness CD disk and the maximum read range is
The characteristics of the proposed architectures were investigated using the
commercial software Mat-Lab and IE3D, and measurements were carried out to verify
the simulations. With the specifically designed antennas, the performance of the
modern intelligent RFID system should improve greatly.|
|Online Catalog Link: ||http://lib.cityu.edu.hk/record=b3947847|
|Appears in Collections:||EE - Doctor of Philosophy |
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