This document describes the design and development of rectangular microstrip antennas for quad-band and triple-band operation. A conventional rectangular microstrip antenna was modified with the addition of slits to achieve multiple frequency bands. Three vertical slits were added to produce a quad-band antenna with bandwidths of 3.75%, 2.52%, 7.3%, and 5.36%. The quad-band antenna was further modified into a triple-band antenna by changing two slits to a horizontal orientation, resulting in bandwidths of 11.2%, 2.22%, and 19.61%. Measurements showed the modified antennas enhanced bandwidth and gain without significantly altering radiation patterns compared to the original single-band antenna. The antennas have potential

1. International Journal of Electronics and Communication Engineering & Technology (IJECET),
ISSN 0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 3, May – June (2013), © IAEME
132
DESIGN AND DEVELOPMENT OF RECTANGULAR MICROSTRIP
ANTENNA FOR QUAD AND TRIPLE BAND OPERATION
P. Naveen Kumar 1*
, S.K. Naveen Kumar 1
and S.N.Mulgi 2
1
Department of Electronics, University of Mysore, P.G. Center, Hemagangothri, Hassan,
Karnataka, India
2
Department of PG Studies and Research in Applied Electronics, Gulbarga University,
Gulbarga-585106, Karnataka, India
ABSTRACT
A novel design and development of rectangular microstrip antenna is realized for
quad band operation from conventional rectangular microstrip antenna (CRMA) by loading
slits on the conducting patch. The quad bands are achieved by incorporating three slits along
the width of CRMA. The magnitude of each operating bands are 3.75%, 2.52%, 7.3%, and
5.36% respectively. Further these quad bands can be converted to triple bands by placing two
slits along the length and one along the width of CRMA without changing the nature of
radiation characteristics. This antenna gives 11.20%, 2.22% and 19.61% of impedance
bandwidth at each operating band and enhances the gain. Details of the antenna designs are
presented and experimental results are discussed. The proposed antennas may find
application in radar communication systems.
Keywords: quad band, triple band, impedance bandwidth, gain.
1. INTRODUCTION
The microstrip antennas (MSAs) are becoming popular in all types of communication
systems because of their attractive features and characteristics such as small size, light
weight, low profile and easy to fabrication [1]. But the main limitations of MSAs are their
narrow impedance bandwidth and lower gain. The antenna operating more than one band of
frequencies are quite attractive because each band can be used independently for
transmit/receive applications. Many researchers have disposed so many techniques in the
literature to realize dual, triple or multiband operation of CRMA by aperture coupling [2],
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2. International Journal of Electronics and Communication Engineering & Technology (IJECET),
ISSN 0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 3, May – June (2013), © IAEME
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corner truncation [3], shorting pins on the patch [4], using stacked patches [5] etc. Among all
slot/slit loading is very simple, easy to incorporate and design. Realization of quad bands
using slit along the width and length of CRMA and conversion of quad bands to triple bands
without much changing the radiation characteristic is found to be rare in the literature.
2. DESIGNING
The proposed antenna are designed using low cost glass epoxy substrate materials of
thickness h=1.66mm, relative permittivity εr = 4.2. Figure 1 shows the geometry of (CRMA)
which is designed by using basic equations available in the literature [1]. The antenna is
designed for the resonant frequency of 4 GHz. The CRMA consists of radiating patch of
length L and width W. The feed arrangement consists of quarter wave transformer of length
Lt and width Wt which is used for better impedance matching between the microstripline
feed of length Lf , width Wf and center point (Cp) along the width of the rectangle
microstripline patch. At the tip of microstrip line feed a 50 coaxial SMA connector is used
for feeding the microwave power.
Fig.1 Geometry of CRMA.
Figure 2 shows the geometry of vertical slits rectangular microstrip antenna
(VSRMSA). Here the three vertical slits are placed along the width of the patch at an equal
distance from the non radiating edges of the patch. The upper vertical slit is placed at a
distance 1.1cm and lower slits are placed at 0.69 cm from the edges of the patch. The length
of the slit is taken as Ls which is equal to 0.75cm and width of the slits is Ws which is equal
to 0.1cm. The dimensions of slits are taken in terms of λ0, where λ0 is the free space
wavelengths in cm corresponding to the design frequency of 4 GHz.

3. International Journal of Electronics and Communication Engineering & Technology (IJECET),
ISSN 0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 3, May – June (2013), © IAEME
134
Fig. 2 Geometry of VSRMSA
Figure 3 shows the geometry of horizontal slits rectangular microstrip antenna
(HSRMSA) which is derived from VSRMSA. In this figure, the lower vertical slits used in
VSRMSA are replaced horizontally and are located at the centre of non radiating edges of the
patch. The design parameters of CRMA, VSRMSA and HSRMSA are given in Table 1.
Table. 1 Designed parameters of CRMSA, VSRMSA and HSRMSA
Fig. 3 Geometry of HSRMSA
L = 1.68 cm W = 2.32cm
Lt = 0.96cm Wt = 0.05cm
Lf = 0.75cm Wf = 0.32cm
Ls = 0.75cm Ws = 0.1cm

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3. EXPERIMENTAL RESULTS
The impedance bandwidth over return loss less than -10dB for the proposed antennas
is measured on vector network analyzer. The variation of return loss versus frequency of
CRMA is shown in Fig. 4. From this figure it is seen that, the antenna resonates for single
band of frequency BW1. The magnitude of BW1 is found to be 3.50% which is calculated
by using the equation,
( )2 1
Bandwidth 100%
c
f f
f
− 
= × 
 
where f2 and f1 are the upper and lower cutoff frequencies respectively, when its return loss
reaches -10dB and fc is the center frequency between f1 and f2.
Figure 5 shows the variation of return loss versus frequency of VSRMSA. From this
figure it is seen that, the antenna resonates for quad band of frequencies BW2, BW3, BW4 and
BW5. The magnitude of each operating band is found to be 3.75%, 2.52%, 7.3% and 5.36%
respectively. The quad band operation is due to the independent resonance of patch and slits
inserted on the conducting patch of VSRMSA [7].
Figure 6 shows the variation of return loss versus frequency of HSRMSA. From this
figure it is seen that, the antenna resonates for triple band of frequencies BW6, BW7 and BW8.
The magnitude of each operating band is found to be 11.20%, 2.33% and 19.6% respectively.
It is clear from the figure that, BW6 is increased from 3.75% to 11.20% when it is
compared with the BW2 of Fig. 4 and also BW4 and BW5 shown in Fig. 5 are merges together
and gives BW8 which is 19.6%. Hence the use of slits in HSRMSA is quite effective in
converting the quad bands to triple bands and enhances the bandwidth at each operating
bands.
-20
-15
-10
-5
0
BW1
5420
ReturnLoss(dB)
Frequency(GHz)
Fig. 4 Variation of return loss versus frequency of CRMSA

5. International Journal of Electronics and Communication Engineering & Technology (IJECET),
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-35
-30
-25
-20
-15
-10
-5
0
BW5
BW4
BW3BW2
161412108642
ReturnLoss(dB)
Frequency(Hz)
Fig. 5 Variation of return loss versus frequency of VSRMSA
The gain of the proposed antennas is measured by absolute gain method. The power
transmitted Pt by pyramidal horn antenna power received Pr by antenna under test (AUT) is
measured independently. With the help of these experimental data, the gain (G) in dB of
AUT is calculated by using the formula,
( ) ( ) 0r
tdB dB
dBt
λP
= 10 log - - 20log
P 4πR
G G
   
  
  
where, Gt is the gain of the pyramidal horn antenna and R is the distance between the
transmitting antenna and AUT. Using the above equation the maximum gain of the VSRMSA
and HSRMSA is found to be 1.5 dB and 3.62 dB respectively. Hence HSRMSA is quite
effective in enhancing the gain from 1.56 to 3.62 dB.
-30
-25
-20
-15
-10
-5
0
161410842 6 12
BW8
BW7
BW6
ReturnLoss(dB)
Frequency(GHz)
Fig. 6 Variation of return loss versus frequency of HSRSMA

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The radiation patterns of antenna are measured in an anechoic chamber. The co-polar
and cross-polar patterns in the E- plane and H- plane of the antenna are presented in Figure 7-
9. The E and H plane radiation pattern of antennas are broadsided in nature and are nearby
same with each other.
Fig. 7 E and H plane radiation patterns of CRMSA measured at 3.97 GHz
Fig. 8 E and H plane radiation patterns of VSRMSA measured at 7.95 GHz
Fig. 9 E and H plane radiation patterns of HSRMSA measured at 7.7 GHz
0-10-20-30-40-50
0
30
60
90
120
150
180
210
240
270
300
330
Eco of Antenna
Hco of Antenna
Ecross of Antenna
Hcross of Antenna
0-10-20-30-40-50
0
30
60
90
120
150
180
210
240
270
300
330
Eco of Antenna
Hco of Antenna
Ecross of Antenna
Hcross of Antenna
0-10-20-30-40-50
0
30
60
90
120
150
180
210
240
270
300
330
Eco of Antenna
Hco of Antenna
Ecross of Antenna
Hcross of Antenna

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4. CONCLUSION
From the detailed experimental study it is concluded that, by using three vertical slits
in CRMSA i.e. VSRMSA makes the antenna to resonate for quad band of frequencies and
gives a peak gain of 1.56 dB. Further by replacing vertical slits into horizontal slits i.e.
HSRMA the antenna converts quad bands to triple bands and gives a maximum impedance
bandwidth of 19.6% in triple bands. This antenna also enhances the gain to 3.62 dB when
compared to the gain of VSRMSA without changing much in the radiation characteristics.
The proposed antennas are simple in their design and fabrication and they use low cost
substrate material. These antennas may find application in radar communication systems.
REFERENCES
[1] I. J. Bahl and P. Bhartia, Microstrip antennas, MA: Artech House, 1982.
[2] M.N. Jazi, Z.H. Firouzeh, H.M. Sadeghi and G. Askari, “Design and implementation of
aperture coupled microstrip IFF antenna”, Progress In Electromagnetic Research
Letters, Vol.4, No.1, 1-5, 2008.
[3] N. Kulkarni, S. N. Mulgi and S. K. Satnoor, “Design and development of corner
truncated U and inverted U-Slot multiband tunable rectangular microstrip antenna”,
Progress In Electromagnetic Research Letters, Vol. 29, 185-199, 2012.
[4] S.C. Pan and K.L.Wong, “Dual frequency triangular microstrip antenna with a shorting
Pin”, IEEE trans Antennas Propag., pp.1889,1997.
[5] K.Oh, B. Kim and J. Choi, “Design of dual and wideband aperture stacked patch antenna
with double-sided notches”, Electron Lett., (UK), 40, pp.643, 2004.
[6] J. Y. Sze and K. L. Wong, (2000). “Slotted rectangular microstrip antenna for bandwidth
Enhancement”, IEEE Trans. Antennas & Propagat., Vol. 48, no. 8, pp. 1149-1152.
[7] Q.Q. Wong, B.Z and J.He, “Wideband and dual-band design of a printed dipole antenna
IEEE Antennas Wireless propag Letter, pp.1, 2008.
[8] Nagraj Kulkarni and S. N. Mulgi, “Corner Truncated Inverted U - Slot Triple Band
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[9] M.Veereshappa and Dr.S.N.Mulgi, “Design and Development of Triple Band
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