1. International Journal of Electronics and JOURNALEngineering & Technology (IJECET), ISSN 0976
INTERNATIONAL Communication OF ELECTRONICS AND
– 6464(Print), ISSN 0976 – 6472(Online) Volume 3, Issue 1, January- June (2012), © IAEME
COMMUNICATION ENGINEERING & TECHNOLOGY (IJECET)
ISSN 0976 – 6464(Print)
ISSN 0976 – 6472(Online)
Volume 3, Issue 1, January- June (2012), pp. 17-22
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DESIGN AND DEVELOPMENT OF TRIPLE BAND
OMINIDIRECTIONAL SLOTTED RECTANGULAR MICROSTRIP
ANTENNA
M. Veereshappa and Dr.S.N Mulgi
Department of PG Studies and Research in Applied Electronics,
Gulbarga University, Gulbarga 585 106, Karnataka, INDIA
mveeresh27@rediffmail.com, s.mulgi@rediffmail.com
ABSTRACT
A novel design of slotted rectangular microstrip antenna is proposed for triple band
operation and ominidirectional radiation characteristics. The proposed antenna is simple
in its geometry and has been constructed from conventional rectangular microstrip
antenna by placing rectangular slots on the patch at a distance of 2 mm from the edges. A
ground plane of height equal to the length of microstripline is placed on the top of the
patch with a gap of 1 mm on either sides of the microstrip line. The triple bands are
achieved in the frequency range of 4.75 GHz to 16 GHz. The magnitude of each
operating band is found to be 5.32, 36.35 and 40.49 % respectively. Experimental results
are in close agreement with the simulated results. The proposed antenna may find
application in microwave communication system.
Keywords: microstip antenna, triple band, slot, ominidirectional
1. INTRODUCTION
Microstrip antennas (MSAs) are useful in microwave communication systems because of
their diversified applications such as light weight, compact, planar configuration, easy to
fabricate and low cost [1]. The antenna operating for more than one band of frequencies
is quite useful because each band can be used independently for transmit receive
applications. Number of investigations have been reported in the literature for the
realization of dual, triple and multiband operations of microstrip antennas [3-9]. But in
this paper a simple technique has been demonstrated to get triple bands and
ominidirectional radiation characteristics in the frequency range of 4.75 to 16 GHz by
loading slots on the conducting patch and by placing a ground plane of height equal to the
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2. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN 0976
– 6464(Print), ISSN 0976 – 6472(Online) Volume 3, Issue 1, January- June (2012), © IAEME
length of microstripline on conventional rectangular microstrip antenna. This
modification does not affect the size of the conventional patch designed for the same
resonant frequency.
2. DESIGN OF ANTENNA GEOMETRY
The art work of the proposed antenna is sketched by using computer software Auto-CAD
to achieve better accuracy and is fabricated on low cost FR4-epoxy substrate material of
thickness of h = 1.6 mm and permittivity εr = 4.4.
Figure 1 shows the top view geometry of triple band slotted rectangular microstrip
antenna (TSRMA). The side view geometry of this antenna is as shown in Fig.2. In Fig.1
the area of substrate is L × W mm. On the top surface of the substrate a ground plane of
height which is equal to the length of microstripline feed Lf is used on either sides of the
microstripline. A gap of 1 mm is used between the ground plane and microstripline feed.
On the bottom of the substrate a continuous copper layer of height Lf is used below the
microstripline. The TSRMA is designed for 3 GHz using the equations available for the
design of conventional rectangular microstrip antenna in the literature [2]. The length and
width of the rectangular patch are Lp and Wp respectively. The feed arrangement consists
of quarter wave transformer of length Lt and width Wt which is connected as a matching
network between the patch and the microstripline feed of length Lf and width Wf. A SMA
connector is used at the tip of the microstripline feed for feeding the microwave power.
In Fig.1 the rectangular slots are placed on the patch from its vertical edges for providing
different surface current paths so as to produce multi resonant modes. The length and
width of slots are Ls and Ws respectively. Both the slots are kept at a distance of 2 mm
from the vertical edges of the radiating patch. The design parameter of the proposed
antenna is given in Table 1.
3. EXPERIMENTAL RESULTS
The antenna bandwidth over return loss less than -10 dB is simulated using HFSS
simulating software and then tested experimentally on Vector Network Analyzer (Rohde
& Schwarz, Germany make ZVK model 1127.8651). The variation of return loss verses
frequency of TSRMA is as shown in Fig. 3. From this graph the experimental bandwidth
(BW) is calculated using the equations,
f −f 
BW =  2 1  ×100 %
 fc 
were, f1 and f2 are the lower and upper cut of frequencies of the band respectively when
its return loss reaches – 10 dB and fc is the center frequency of the operating band. From
this figure, it is found that the antenna operates between 4.75 to 16 GHz.
In Fig. 3 it clearly seen that the antenna gives three resonant modes. The resonant mode
at 4.84 GHz is due to the fundamental resonant frequency of the patch and others modes
at 8.94 GHz and 14.01 GHz are due to the novel geometry of TSRMA. The magnitude of
experimental -10 dB bandwidth measured at BW1 to BW3 are 260 MHz, 3.113 GHz and
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3. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN 0976
– 6464(Print), ISSN 0976 – 6472(Online) Volume 3, Issue 1, January- June (2012), © IAEME
5.27 GHz respectively. The simulated results of TSRMA is also shown in Fig.3. The
experimental and simulated results are in close agreement with each other.
The co-polar and cross-polar radiation pattern of TSRMA is measured in its operating
bands. The typical radiation patterns of TSRMA measured at 8.94 GHz and 14.01 GHz
are shown in Fig 4 and 5 respectively. The obtained patterns are ominidirectional in
nature.
4. CONCLUSION
From the detailed experimental study, it is concluded that the TSRMA derived from
conventional rectangular microstrip antenna is quite capable in producing triple band
operation in the frequency range of 4.75 to 16 GHz. The antenna gives ominidirectional
radiation characteristics in its operating bands. The simulated and experimental return
loss results of TSRMA are in close agreement with each other. The proposed antenna is
simple in its design and fabrication. The antenna is constructed using low cost substrate
material. This antenna may find any applications for the systems operating between 4.75
to 16 GHz
ACKNOWLEDGEMENTS
The authors would like to thank Dept. of Sc. & Tech. (DST), Govt. of India. New Delhi,
for sanctioning Vector Network Analyzer to this Department under FIST project. The
authors also would like to thank the authorities of Aeronautical Development
Establishment (ADE), DRDO Bangalore for providing their laboratory facility to make
antenna measurements on Vector Network Analyzer.
REFERENCES
1 Constantine A. Balanis (1997). “Antenna theory analysis and design,” John
Wiley, New York.
2 I. J. Bahl and P. Bharatia (1981). “Microstrip antennas,” Dedham, MA: Artech
House, New Delhi.
3 H. K. Kan. Waterhouse. A. Y. J. Lee and Pavlickovski (2005). “Dual frequency
stacked shorted patch antenna.” Electron lett.Vol.41, No.11, pp. 624-626.
4 C.-H. Cai, J. –S Row and K. –L. Wong, (2006). “Dual frequency microstip
antenna with dual circular polarization.” Electron lett. Vol. 42, No. 22, pp. 1261-
1262.
5 S. Maci, G. Biffi Gentili P. Piazzesi and C. Salvador (1995), “Dual-band slot
loaded patch antenna,” IEEE Proceedings on Microwave Antennas
Propagation, No.142, pp.225-232.
6 K. L Wong and K. B. Hsieh (1998),“Dual frequency circular microstrip antenna
with a pair of arc-shaped slots,” Microwave Optical Technology Letters, Vol.
19, pp. 410-412.
7 S. T. Fang and K. L. Wong (1999), “A dual frequency equilateral - Triangular
microstrip antenna with a pair of narrow slots,” Microwave Optical Technology
Letters, Vol. 23, pp. 82-84.
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4. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN 0976
– 6464(Print), ISSN 0976 – 6472(Online) Volume 3, Issue 1, January- June (2012), © IAEME
8 S.Hong and K.Chang (2006),”Single-feed triple-frequency rectangular microstrip
patch antenna with pairs of spur-lines,”Electron lett.Vol. 42, No.12, pp. 673-674.
9 K. G. Thomas and M. Sreenivasan, (2009),”Compact triple band antenna for
WLAN, WiMAX applications,” Electron lett.Vol.45, No.16, pp.811-813.
TABLE I DESIGN PARAMETERS OF PROPOSED ANTENNAS
Antenna Dimension in
Parameters mm
Lp 23.4
Wp 30.4
Lf 24.8
Wf 3.0
Lt 12.4
Wt 0.5
L 80.0
W 50.0
Ls 20.4
Ws 5.0
Figure 1 Top view geometry of TSRMA
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5. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN 0976
– 6464(Print), ISSN 0976 – 6472(Online) Volume 3, Issue 1, January- June (2012), © IAEME
Figure 2 Side view geometry of TSRMA
Figure 3 Variation of return loss versus frequency of TSRMA
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6. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN 0976
– 6464(Print), ISSN 0976 – 6472(Online) Volume 3, Issue 1, January- June (2012), © IAEME
Figure 4 Radiation pattern of TSRMA measured at 8.94 GHz
Figure 5 Radiation pattern of TSRMA measured at 14.01 GHz
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