IJEEE, Vol. 1, Issue 4 (August, 2014)
e-ISSN: 1694-2310 | p-ISSN: 1694-2426
MICROSTRIP PATCH ANTENNA WITH CROSS-SLOT FOR UHF RFID HANDHELD READER APPLICATIONS 1
Neha Saini, 2Vijay Kumar
1,2
E.C.E Department, Punjab College of Engineering and Technology, Punjab, India 1
neha.saini22@gmail.com , 2nanovijay1@gmail.com
Abstract— This paper presents a microstrip patch antenna with cross-slot for UHF RFID handheld reader applications. A square patch with unequal length crossslot and diagonally symmetrical two circular and two square slots are used to acheive compact size. The coaxial feed is used to excite the proposed antenna. The 10dB return loss bandwidth and VSWR of proposed antenna are 15.5MHz (914.3-929.8) and 1.6 respectively. Index Terms— Microstrip Patch Antenna, Radio Frequency Identification, RFID Reader Antenna, Return Loss, VSWR (Voltage Standing Wave Ratio). I. INTRODUCTION It is an automatic identification technology. This technology provides wireless identification and tracking. This technology is more convenient than use of bar codes and optical scanners [1]. Because it can transmits data without contact and Line-Of-Sight. Thus, the tagged items can be identified within the field without regard to orientation or position to affixed tag. The information is sent to and read from RFID tags by the reader using radio waves. This allows for many items to be interrogated instanteounsly without manual manipulation of the items. The information is sent to and read from RFID tags using radio waves. A RFID system typically consists of Tag Reader Information Management System [2].
Figure 1 RFID System
A. Tag RFID tag is an electronic circuit that exchanges data with an RFID reader through radio waves. Tags are data carrying devices, so also called as transponder. RFID tag consists of two main parts: International Journal of Electrical & Electronics Engineering 30
Integrated circuit (IC) and Antenna. IC is used for processing and storing data as well as modulating and demodulating radio waves transmitted /received by antenna. Antenna receives the radio waves. Due to dynamically functionality of tags, information can be added, modified or stored on a tagged item. RFID Tags can be classified into three categories on the basis of communication between tag and reader and these are active RFID tag, semi active RFID tag and passive RFID tag [3]. B. Reader It is also called as an interrogator. The means of interrogation is a wireless and because the distance is relatively short, the line of sight between the reader and tag is not necessary. It contains an antenna to transmit information to the tag as well as receive information from tag. RFID reader can be active RFID reader and passive RFID reader on the basis of communication between tag and reader. RFID reader can also be classified based upon the application fixed RFID reader and mobile RFID reader [4]. C. Information Management System An RFID system can be interfaced to an IT platform for exchange of information. Sometimes the host system is needed to collect the data to convert into useful information for the end-user. To have its longer read range, higher data transmission rate as well as larger storage capacity, UHF system are gaining more popularity compared to low frequency (LF), high frequency (HF), systems. It is known that operating frequencies of each country varies from one another in UHF RFID system because it is not universal worldwide [5]. The frequency is from 840 MHz to 960 MHz with different sub-bands such as 902928 MHz for North-South America, 865-867 MHz for Europe and 840-955 MHz for Asia-Pacific region. In Asia-Pacific region, the UHF RFID frequency ranges from 840 MHz to 955MHz in different countries: China (840.5-844.5 MHz, 920.5-924.5 MHz), Japan (952-955 MHz), India (865-867MHz), Hong Kong (865-868 MHz, 920-925 MHz), Taiwan (920-928 MHz), Korea (908.5-910 MHz, 910-914 MHz), Singapore (866-869 MHz, 923-925 MHz), Australia (920-926 MHz), etc. [6]. In RFID system the reader antenna is the one of the important component. For handheld RFID reader applications the overall size of antenna should be small. www.ijeee-apm.com