2014 International Conference on Electronics and Communication System (lCECS -2014)
Dual Band Dipole Antenna for RFID/WSN Applications K K Aju John,Jacob Abraham,Thomaskutty Mathew Department ofElectronics, UCAS M G University Regional center, Edapally
Kochi, Kerala, India
[email protected]
Abstract-The Design and antenna proposed
for
the
dual
development of a dual band
RFIDIWSN
band
application
antenna
operates
is
in
dipole
reported.
the
UHF
The RFID
In this paper a dual band Printed dipole antenna is designed for the RFID/WSN application. This antenna
resonate at 867
MHz and 2.45GHz, which are the operating frequency bands of
frequency bands, which are 867-925 MHz and 2.45-2.47 GHz.
RFID in India. The antenna
Good radiation characteristics and good impedance matching are
fabricated, the simulated and measured result shows that the
achieved
proposed antenna can be successfully cover the spectrum the
at
the
two
bands
without
any
external
matching
circuitry. The return loss of the dual band antenna is less than
-10
dB in both the bands. This type of small size multiband
antenna is suitable for RFID readers integrated to wireless sensor network.
867MHz
(866
is designed,
MHz-925MHz)
and
simulated and
2.45GHz
(2.45GHz-
2.47GHz) for RFID/WSN communication. ANTENNA DESIGN AND FABRICA nON
II.
The present work, an antenna with dual band characteristics
Keywords- dual band; RFID; WSN ;dipole antenna;
are studied. Fig 1 shows the geometry and structure of the proposed dual band printed dipole antenna for RF-ID and
I.
INTRODUCTION
Radio
WSN applications. The dipole is printed on the top side of the
Frequency
Wireless Sensor
Network
Identification (WSN)
and
substrate. The antenna is fabricated on a 1.6 mm thick FR-4
important
substrate that has a loss tangent of 0.02; relative permittivity
(RFID)
are
two
of
Cr44. The proposed dual band Printed Dipole Antenna (PDA)
potentials. RFID
was simulated and the perfonnance investigated theoretically
systems are mainly used to identify objects or to track their
by using computer simulation technology CST-Microwave
location without providing any indication about the physical
studio .The antenna was fabricated and tested experimentally.
wireless
technologies
applications and
that
provide
have
limitless
wide
future
variety
condition of the object. WSNs on the other hand, are networks
The measurements were carried out using H P 8510C network
of small, cost-effective devices is
analyzer.
usually used to sense and
monitor physical, chemical, and biological through
sensing
of
integration of the
environments
sound, temperature, light, etc. The
RFID and WSNs can maximize their
effectiveness, extends it range, give new perspectives to a broad range of useful applications, the resulting integrated
L1
-
Structure
n
technology will have extended capabilities, scalability, and
L6
portability as well as reduced unnecessary costs. There is a
L2
great range of possible integration approaches of RFID and
L3
WSN in the supply chain management [1-2].
��
L5
LB
With
the
rapid
progress
in
RFID/WSN
communication, the antenna development is demanded with multi-band operations in the UHF and Microwave bands. Printed dipole antennas have found distributed applications in RFID and WSN systems [3-5], due to the simplicity in the design,
reduced
size and widespread operation
MHz-925MHz)
and
2.45GHz
(2.45GHz-2.47GHz)
bands. The use of the dual band technology enables a single antenna to operate in to two different standards [7-9].
w
[6]. The
proposed antenna is designed to be operated in the 867MHz (866
T
FR4 Substrate
L4
Fig l.Geometry and structure of the proposed antenna
L
2014 International Conference on Electronics and Communication System (lCECS -2014)
The fabricated dual band printed dipole antenna is shown in figure 2. A 50 n impedance SMA connector is used for the excitation , resulting in a return loss lower than the -10 dB at both frequency bands. Geometry of the antenna consist of length L=35mm and width W=76mm. Table (l) shows the design parameters of the proposed antenna.
X-YPlane
1-___
ae7MH�X'YplwleCoopOllo &e1MH,X·YpllneC.-pde
1
I
y..z Plane 1 H Y -18 M .1. -ZplrleCo-poIe --- M1MH.oY-ZplaneCtots1"*
l
Fig 2. Fabricated dual band printed dipole antenna. Table
W
(I) Parameter list of the fabricated antenna.
= 76 mm
h = l.6 mm L
L2
= 31.14 mm
L3
= 14.41 mm
L6= 9.73 mm
L7= 3.0 mm L8=
L4= 4.62 mm
= 35 mm
LJ = 10.20 mm
2.0 mm
x-z Plane
ee71YHl: 1---- ee ",",X·x,zZ� �1
Ls = 6.l3 mm
Fig4. Measured radiation patterns (normalized) of the proposed antenna at MHz.
III.
866
RESULT AND DISCUSSIONS The figure 3 shows the simulated and experimental
results of the return loss for the antenna design of Figure 1.
It is clearly seen that good agreement between the measured and simulated results is obtained. From the measured results,
The return loss of the antenna shows dual band characteristics
the lower band has a bandwidth (lO.O-dB return loss) of
in the desirable frequency range.
96MHz, covering the RFID UHF band. For the upper band has a band width of 400 MHz covering the RFID/ WSN band.
5 .-------�
Tab.2. Comparison of measured and simulated return loss and bandwidth in tabular form -5
10
-10
!!2
-15
I
�
-20
/
Parameters
\ I \ I \ I \1
Measured Sinulated
Resonant Frequency
Simulated
Measured
Lower Band
Upper Band
Lower Band
Upper Band
870 MHz
2.47 GHz
866 MHz
2.45GHz
-12.7dB
-24.4 dB
-13.05dB
-14.37dB
450 MHz
96 MHz
400 MHz
J
-25
SII
-30 0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
Frequency GHz
Fig 3.Comparison of simulated and measured return loss of the proposed dual band antenna for RFID application.
Band Width (-10 dB)
78 MHz
2014 International Conference on Electronics and Communication System (lCECS -2014)
ACKNOWLEDGMENT Authors wish to acknowledge the encouragement and support received from Dr. C. K Aanandan, Professor, Department of Electronics, Cochin University of Science & Technology, Kochi, India. REFERENCES X-YPlane
1_2A5GH�X'Ypl.:o..cg.pd. 1 . -- 2....SOHlJ
