Summary
International Symposium on Antennas and Propagation
2009
Session Number:3B2
Session:
Number:3B2-1
A Study on Effects of Conductive Layer Thickness on Performance of UHF RFID Tags
Taweesak Sanpechuda, Pornanong Pongpaibool,
pp.847-850
Publication Date:2009/10/21
Online ISSN:2188-5079
Summary:
Nowadays, the Radio Frequency Identification (RFID) is applied on many applications such as transportation, inventory and traceability. When comparing with the bar code, the RFID tags are more desirable on properties such as non-line-of-sight communication and high data storage [1]. When comparing the operating frequency of RFID tags between HF and UHF, the later one is likely to benefit from a long-range reading. However, the price of UHF RFID tags is still too high for commercial use. To reduce the price, the appropriate method of producing the RFID tags should be realized. In general, there are two main methods to produce the RFID tags. The first one is the subtractive method which the conductor covered on the substrate such as FR4 is etched by the photolithographic process following the shape of designed antenna [2]. This method results in the much loss of conductor and the chemical solvent for etching process. The other is the additive method which the conductive ink is directly printed on the substrate. The advantage is that conductive ink is not wasted. However, most of the conductive ink has low conductivity comparing with copper or silver. This can cause the decrease in the RFID tag performance. To increase the performance, the conductive layer thickness needs to be increased. This means the more quantity of the conductive ink and the higher costing. It is known that the amount of current flow in each area of the antenna is different, where the feeding point tends to be the area with the highest current flow. When the conductive layer thickness in high current flow area is increased, the performance of the RFID tags would be increased too [3]. In this paper, we study the effects of the conductive layer thickness on the performance of the UHF RFID tags. To achieve the highest performance RFID tags, various structures and thickness ratios of conductive layer are varied while the quantity of the conductor is controlled. In the second section, the evaluation procedure and antenna configurations are described. In the evaluation, the conventional dipole antenna and the dipole antenna with the inductive matching network are used. The third section is the results and discussions. The fourth section is the comparison of the effects of conductive layer thickness on the RFID tag read range. The last section is the conclusions.