Ribbon Beam Antenna for RFID Technology Tom Zlabsk Department of - - PowerPoint PPT Presentation

Department of Electrical Engineering 7.11. 2013

Ribbon Beam Antenna for RFID Technology

Tomáš Zálabský

Department of Electrical Engineering 7.11. 2013

INTRODUCTION

1

• The developed antenna is a part of a railway information system.
• This system consists of RFID tags situated on trains and of RFID

readers located near to railway lines, communicating with an information center.

• Nowadays antennas with circular radiation pattern in horizontal

plane are used for these readers or in the ribbon radio networks.

• These types of antennas do not use radiated power effectively

because they radiate much power in the front direction.

• Another possibility is to use two Yagi antennas oriented to the
• pposite sides along rails
• This system has disadvantage in very low radiation in the

transverse directions.

• Normally the low coverage at short distances is not a problem but

in our application (RFID) is necessary to cover near distances too.

Department of Electrical Engineering 7.11. 2013

OBJECTIVES

2

• The aim of this work was to design the antenna with

cosecant radiation pattern on frequency 2.45 GHz.

• This shape of the radiation pattern was chosen for the

best coverage of the railway line

• In reality we can only approach to this curve because

a real antenna generates a rippled antenna response.

Department of Electrical Engineering 7.11. 2013

MATERIAL & METHOD

3

• Antenna system consists of two identical mirrors oriented antenna

parts so we may design one part of the whole antenna only.

• There are three dielectric layers.
• On the top side of this layer a feeder circuit is situated consisting of

power dividers of Wilkinson and branch-line types.

• The second layer is made of a dielectric material and it is used for

mechanical distance definition between the first and the third layer.

• The third layer carrying radiating elements – patches.
• Patch elements create the antenna array.

Department of Electrical Engineering 7.11. 2013

RESULTS

4

• The measured return loss of one patch element is shown. There is

evident a good impedance match of the patch at the centre frequency. The return loss level is quite acceptable even in the range of 100 MHz.

• The measured results of power dividers are presented on next picture.

Department of Electrical Engineering 7.11. 2013

RESULTS

5

• The measured reflection coefficient of the whole antenna system
• The measured radiation pattern of the whole antenna structure

1 1.5 2 2.5 3 3.5 4 x 109

• 35
• 30
• 25
• 20
• 15
• 10
• 5

Průběh S-parametrů f [Hz] magnitude [dB]

X: 2.448e+009 Y: -24.31

S11

Department of Electrical Engineering 7.11. 2013

ACKNOWLEDGEMENT & CONTACT

6

Tomáš Zálabský tomas.zalabsky@student.upce.cz Department of Electrical Engineering

Faculty of Electrical Engineering and Informatics University of Pardubice Czech Republic http://www.upce.cz/en/fei/ke.html The research was supported by the Internal Grant Agency

• f University of Pardubice, the project No. SGFEI 09/2013

and by the Czech Ministry of Industry and Trade, the research project No. FR TI-2/480.