Author:
Ayşe Zeynep SAYLAN
Year:
2011
Abstract:
RFID systems have become very popular in recent years due to their wide area of usage. RFID systems are used in supply chain, security related areas, logistics, and so on. By using RFID system, human based errors can be eliminated so the costs can be reduced. The RFID systems are composed of four main components; namely the reader, the antenna, the tag and the computer.In this master thesis, a linear polarized UHF RFID antenna and a multiplexer are designed and fabricated to reduce RFID equipment costs. Wide reading range can be achieved using a multiplexer instead of multiple RFID reader. The designed antenna is cheaper than the antennas in the industry while presenting similar operational parameters.The designed UHF RFID antenna is simulated from 850 MHz to 880 MHz. Return loss of the antenna is lower than -10dB in the range of 855 MHz to 875 MHz. The fabricated antenna has an input impedance of , a return loss of -18.57 dB, a relatively high gain of 5.4 dBi and a read range of 8 meters at 2 Watt reader power. The fabrication cost of a single antenna is around 15 $ which is fairly cheap. The operation parameters are similar to the antennas in the industry, since conventional materials and components are used. Cost reduction can be achieved by using the presented antenna.A multiplexer is designed and fabricated to multiplex the RFID reader port to two ports and extend the read range of the RFID reader. The main contribution in this design is the usage of pin diodes which are very cheap and easy to find. This in return reduces the fabrication costs. The designed circuit has only a few components, thus a relatively low complexity. It is easy to replace any component in case of a failure. The multiplexer is controlled by a PIC which allows the user to determine the read times of each RFID reader antenna. This innovative design allows a cheap solution to wide area applications of RFID where multiple antenna usage is necessary to read every tag in the reading zone.