Abstract : This paper investigate some methods for converting single band antennas to multiband antennas so that all single band antennas convert in multiband antennas and gives multiband facility without increasing the cost of manufacturing. Simulation is performing on Ansoft HFSS and corresponding result are shown by figures. Impedance bandwidth, VSWR and Return loss are observed for the proposed antenna. This proposed patch antenna is suitable for implementing low cost and high stable pattern. Details of the measured and simulated results are presented and discussed

Jitendra Sharma

Nidhish Tiwari

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International Journal of Enhanced Research in Science Technology & Engineering, ISSN: 2319-7463 
Vol. 3 Issue 7, July-2014, pp: (117-123), Impact Factor: 1.252, Available online at: www.erpublications.com 
Page | 117  
 
Multibanding of Microstrip Patch Antenna by 
Feeding Point and Patch Position 
Jitendra Sharma
1
, Nidhish Tiwari
2
 
1
M.Tech. Student, Jagan Nath University, Jaipur, Rajasthan, India 
2
Associate Prof., Jagan Nath University, Jaipur, Rajasthan, India 
 
 
 
Abstract : This paper investigate some methods for converting single band antennas to multiband antennas so that all single 
band antennas convert in multiband antennas and gives multiband facility without increasing the cost of manufacturing. 
Simulation is performing on Ansoft HFSS and corresponding result are shown by figures. Impedance bandwidth, VSWR 
and Return loss are observed for the proposed antenna. This proposed patch antenna is suitable for implementing low cost 
and high stable pattern. Details of the measured and simulated results are presented and discussed.  
 
Index Terms: Microstrip Antenna, Resonant Frequency, Return Losses, Bandwidth. 
 
 
 
I. INTRODUCTION 
 
In high performance aircraft, spacecraft, satellite, and missile applications where size, weight, cost, performance, ease 
of installation, low profile, easy integration to circuits, high efficiency antennas may be required. Presently there are 
many other government and commercial applications, such as mobile radio and wireless communication. [1]To meet 
these requirements microstrip antenna can be used. There are several types of microstrip antennas (also known as 
printed antennas) the most common of which is the microstrip patch antenna or patch antenna. A patch antenna is a 
narrowband, wide-beam antenna. These antennas are low profile, conformal to planar and non-planar surface, simple 
and inexpensive to manufacture using modern printed circuit technology, mechanically robust when mounted on rigid 
surface, compatible with MMIC designs and when the particular shape and mode are selected they are very versatile in 
terms of resonant frequency, polarization, field pattern and impedance. Microstrip antenna consist of a very thin 
metallic strip (patch) placed a small fraction of a wavelength above a ground plane. The patch is generally made of 
conducting material such as copper or gold and can take any possible shape. The radiating patch and the feed lines are 
usually photoetched on the dielectric substrate. The patch and ground plane are separated by dielectric material. Patch 
and ground both are fabricated by using conducting material. [2] 
 
However the major disadvantage of the microstrip patch antenna is its inherently narrow impedance bandwidth. Much 
intensive research has been done in recent years to develop bandwidth enhancement techniques.[7] The most desirable 
for good antenna performance are thick substrates whose dielectric constant is in the lower end of the range because 
they provide better efficiency, larger bandwidth, loosely bound fields for radiation into space, but at the expense of 
larger element size. These techniques include the utilization of thick substrates with low dialectic constant. The uses of 
electronically thick substrate only result in limited success because a large inductance is introduced by the increased 
length of the probe feed, resulting few percentage of bandwidth at resonant frequency.  
 
 A. Basic principles of operation 
 
The metallic patch essentially creates a resonant cavity, where the patch is the top of the cavity, the ground plane is 
the bottom of the cavity, and the edges of the patch form the sides of the cavity. The edges of the patch act 
approximately as an open-circuit boundary condition. Hence, the patch acts approximately as a cavity with perfect 
electric conductor on the top and bottom surfaces, and a perfect “magnetic conductor” on the sides. This point of view 
is very useful in analyzing the patch antenna, as well as in understanding its behavior. Inside the patch cavity the 
electric field is essentially z directed and independent of the z coordinate. Hence, the patch cavity modes are described 
by a double index(m,n). For the (m,n) cavity mode of  the square patch the electric field has the form 
 
 
Where L is the patch length and W is the patch width. The patch is usually o p e ra t ed  in the (1,0) mode ,sothat L 
is the resonant dimension, and the field is essentially constant in the y direction. The surface current on the bottom of 
the metal patch is then x directed, and is given by 
International Journal of Enhanced Research in Science Technology & Engineering, ISSN: 2319-7463 
Vol. 3 Issue 7, July-2014, pp: (117-123), Impact Factor: 1.252, Available online at: www.erpublications.com 
Page | 118  
 
 
For this mode the patch may be regarded as a wide micro strip line of width W ,having a resonant length L that is 
approximately  one-half wavelength in the dielectric. The current is maximum at the centre of the patch, x=L/2, 
while the electric field is maximum at the two “radiating” edges, x=0 and x=L. The width W is usually chosen to be 
larger than the length (W=1.5Listypical) to maximize the bandwidth, since the bandwidth is proportional to the 
width. (The width should be kept less than twice the length, however, to avoid excitation of the (0, 2) mode). Here we 
are using square type microstrip patch antenna, so we have equal length and width of patch antenna. At first glance, it 
might appear that the microstrip antenna will not be an effective radiator when the substrate is electrically thin, since 
the patch current will be effectively shorted by the close proximity to the ground plane. If the modal amplitude A10 
were constant, the strength of the radiated field would in fact be proportional to h. However, the Q of the cavity 
increases as h decreases (the radiation Q is inversely proportional to h). Hence, the amplitude A10 of the modal field 
at resonance is inversely proportional to h. Hence, the strength of the radiated field from a resonant patch is 
essentially independent of h, if losses are ignored. There sonant input resistance will likewise be nearly independent 
of h. This explains why a patch antenna can be an effective radiator even for very thin substrates, although the 
bandwidth will be small. 
 
A10 of the modal field at resonance is inversely proportional to h. Hence, the strength of the radiated field from a 
resonant patch is essentially independent of h, if losses are ignored. The resonant input resistance will likewise be 
nearly independent of h. This explains why a patchant. 
 
   B. Resonant frequency 
 
The resonance frequency for the (1, 0) mode is given by 
 
Where c is the speed of light in vacuum. To account for the fringing of the cavity fields at the edges of the patch, the 
length, the effective length Le is chosen as 
                 
Le=L+2ΔL 
The Hammers tad formula for the fringing extension is 
 
Where 
 
 C. Bandwidth 
 
The bandwidth increases as the substrate thickness increases (the bandwidth is directly proportional to h if conductor, 
dielectric, and surface-wave losses are ignored). However, increasing the substrate thickness lowers the Q of the 
cavity, which increases spurious radiation from the feed, as well as from higher-order modes in the patch cavity. 
Also, the patch typically becomes difficult to match as the substrate thickness increases beyond a certain point 
(typically about 0.05 λ0). This is especially true when feeding with a coaxial probe, since a thicker substrate results in 
a larger probe inductance appearing in series with the patch impedance. However, in recent years considerable effort 
has been spent to improve the bandwidth of the microstrip antenna, in part by using alternative feeding schemes. The 
aperture-coupled feed is one scheme that overcomes the problem of probe inductance, at the cost of increased 
complexity. 
Lowering the substrate permittivity also increases the bandwidth of the patch antenna. However, this has the 
International Journal of Enhanced Research in Science Technology & Engineering, ISSN: 2319-7463 
Vol. 3 Issue 7, July-2014, pp: (117-123), Impact Factor: 1.252, Available online at: www.erpublications.com 
Page | 119  
 
disadvantage of making the patch larger. Also, because the of the patch cavity is lowered, there will usually be 
increased radiation from higher-order modes, degrading the polarization purity of the radiation. 
By using a combination of aperture-coupled feeding and a low-permittivity foam substrate, bandwidths exceeding 
25% have been obtained. The use of stacked patches (a parasitic patch located above the primary driven patch)can 
also be used to increase bandwidth even further, by increasing the effective height of the structure and by creating a 
double-tuned  resonance effect. 
      
II.   ANTENNA DESIGN 
 
The single band rectangular microstrip antenna is shows in figure 2.1. In this the dielectric substrate has two surfaces 
these surfaces are fully metalized. First surface is known as ground plane and the second surface is known as patch. 
Copper is used as a coaxial feed. The thickness, height and position of feeding is shown in figure 2.1. 
 
 
Figur 2.1: Feeding position (Antenna A) 
 
The antenna A is a single band antenna. The feed point of patch antenna is at center (45, 45).In the first method if we 
change the feeding point position right or left from the center with in the patch but patch position remains as it is then 
this antenna works on triple Band. In the second method multibanding is achieved by moving the patch position from 
right or left from the center with in the boundary limits and feeding point kept fix then this antenna also works on triple 
band. This antenna is known as Multiband Antenna. By changing the length of these slots we can change resonant 
frequency and can convert single band antenna to a multiband antenna..These multiband antennas are known as Antenna 
“B” feeding position (45, 54) and Antenna “C” patch position    (30, 21) as shown in figure 2.2 and 2.3 respectively. 
The coaxial feed is used for feeding. The thickness, height and position of feeding are shown in figure 2.2. 
 
 
Figure 2.2: Feeding position (Antenna B) 
International Journal of Enhanced Research in Science Technology & Engineering, ISSN: 2319-7463 
Vol. 3 Issue 7, July-2014, pp: (117-123), Impact Factor: 1.252, Available online at: www.erpublications.com 
Page | 120  
 
 
Figure 2.3: Feeding Position (Antenna C) 
 
III.   RESULTS AND DISCUSSION 
 
The simulation is done on Ansoft HFSS. Single band microstrip patch antenna simulation model of antenna A is shown 
in figure 3.1. The coaxial feed used in designed to have a radius of 0.7 mm. The center frequency is selected as the one 
at which the return loss is minimum. 
 
 
 
Figure 3.1. Simulation model of Patch Antenna (Antenna A) 
 
 
Return loss and antenna bandwidth: 
 
The bandwidth of this patch antenna is 52 MHz and a center frequency 2364 MHz is obtained. Figure 3.2 shows the 
Return loss (in dB) is plotted as a function frequency.  
 
 
 
Figure 3.2: Return loss of patch antenna (Antenna A) 
1.50 2.00 2.50 3.00 3.50 4.00 4.50
Freq [GHz]
-35.00
-30.00
-25.00
-20.00
-15.00
-10.00
-5.00
0.00
d
B
(S
t(
w
a
v
e
p
o
rt
1
_
T
1
,w
a
v
e
p
o
rt
1
_
T
1
))
HFSSDesign1XY Plot 2 ANSOFT
Curve Info
dB(St(w aveport1_T1,w aveport1_T1))
Setup1 : Sw eep
International Journal of Enhanced Research in Science Technology & Engineering, ISSN: 2319-7463 
Vol. 3 Issue 7, July-2014, pp: (117-123), Impact Factor: 1.252, Available online at: www.erpublications.com 
Page | 121  
 
VSWR: 
 
Voltage standing wave ratio (VSWR) is an important property of patch antenna. Figure 3.3 shows the VSWR (in dB) is 
plotted as a function frequency. The VSWR of this antenna at center frequency is 0.41 dB. 
 
 
Figure 3.3: VSWR of Patch antenna (Antenna A) 
 
Simulation model of antenna B  is shown in figure 3.4 
. 
 
 
Figure 3.4: Simulation model of patch antenna (Antenna B) 
 
Return loss and antenna bandwidth: 
 
The bandwidth of First Band of this patch antenna is 49 MHz and a center frequency 2366 MHz, bandwidth of Second 
Band of this patch antenna is 95 MHz and a center frequency 3081 MHz and bandwidth of Third Band of this patch 
antenna is 60 MHz and a center frequency 3970 MHz are obtained. Figure 3.5 shows the Return loss (in dB) is plotted as 
a function frequency.  
 
Figure 3.5: Return Loss of patch Antenna (Antenna B) 
 
VSWR: 
 
Voltage standing wave ratio (VSWR) is an important property of patch antenna. Figure 3.6 shows the VSWR (in dB) is 
plotted as a function frequency. The VSWR of first band at center frequency is 1.68 dB, VSWR of second band at center 
frequency is 4.47 dB and VSWR of Third band at center frequency is 2.7 dB. 
1.50 2.00 2.50 3.00 3.50 4.00 4.50
Freq [GHz]
0.00
10.00
20.00
30.00
40.00
50.00
d
B
(V
S
W
R
t(
w
a
ve
p
o
rt
1
_
T
1
))
HFSSDesign1XY Plot 3 ANSOFT
Curve Info
dB(VSWRt(w aveport1_T1))
Setup1 : Sw eep
1.50 2.00 2.50 3.00 3.50 4.00 4.50
Freq [GHz]
-20.00
-17.50
-15.00
-12.50
-10.00
-7.50
-5.00
-2.50
0.00
d
B
(S
t(
w
a
v
e
p
o
rt
1
_
T
1
,w
a
v
e
p
o
rt
1
_
T
1
))
HFSSDesign1XY Plot 4 ANSOFT
Curve Info
dB(St(w aveport1_T1,w aveport1_T1))
Setup1 : Sw eep
International Journal of Enhanced Research in Science Technology & Engineering, ISSN: 2319-7463 
Vol. 3 Issue 7, July-2014, pp: (117-123), Impact Factor: 1.252, Available online at: www.erpublications.com 
Page | 122  
 
 
Figure 3.6: VSWR of Patch Antenna (Antenna B) 
 
Simulation model of antenna C  is shown in figure 3.7 
 
 
Figure 3.7: Simulation model of patch antenna (Antenna C) 
 
Return loss and antenna bandwidth: 
 
The bandwidth of First Band of this patch antenna is 46 MHz and a center frequency 2378 MHz, bandwidth of Second 
Band of this patch antenna is 92 MHz and a center frequency 3086 MHz and bandwidth of Third Band of this patch 
antenna is 60 MHz and a center frequency 3976 MHz are obtained Figure 3.8 shows the Return loss (in dB) is plotted as 
a function frequency.  
 
 
 
Figure 3.8: Return Loss of patch Antenna (Antenna C) 
 
VSWR: 
 
Voltage standing wave ratio (VSWR) is an important property of patch antenna. Figure 3.9 shows the VSWR (in dB) is 
plotted as a function frequency. The VSWR of first band at center frequency is 1.8 dB, VSWR of second band at center 
frequency is 4.6 dB and VSWR of Third band at center frequency is 2.95 dB. 
 
 
 
Figure 3.6: VSWR of Patch Antenna (Antenna C) 
1.50 2.00 2.50 3.00 3.50 4.00 4.50
Freq [GHz]
0.00
10.00
20.00
30.00
40.00
50.00
d
B
(V
S
W
R
t(
w
a
v
e
p
o
rt
1
_
T
1
))
HFSSDesign1XY Plot 5 ANSOFT
Curve Info
dB(VSWRt(w aveport1_T1))
Setup1 : Sw eep
1.50 2.00 2.50 3.00 3.50 4.00 4.50
Freq [GHz]
-22.50
-20.00
-17.50
-15.00
-12.50
-10.00
-7.50
-5.00
-2.50
0.00
dB
(S
t(w
av
ep
or
t1
_T
1,
w
av
ep
or
t1
_T
1)
)
HFSSDesign1XY Plot 27 ANSOFT
Curve Info
dB(St(w aveport1_T1,w aveport1_T1))
Setup1 : Sw eep
1.50 2.00 2.50 3.00 3.50 4.00 4.50
Freq [GHz]
0.00
10.00
20.00
30.00
40.00
50.00
dB
(V
S
W
R
t(w
av
ep
or
t1
_T
1)
)
HFSSDesign1XY Plot 28 ANSOFT
Curve Info
dB(VSWRt(w aveport1_T1))
Setup1 : Sw eep
International Journal of Enhanced Research in Science Technology & Engineering, ISSN: 2319-7463 
Vol. 3 Issue 7, July-2014, pp: (117-123), Impact Factor: 1.252, Available online at: www.erpublications.com 
Page | 123  
 
CONCLUSIONS 
 
For antenna a bandwidth of patch antenna is 52 MHz and a center frequency 2364 MHz is obtained. The VSWR of this 
antenna at center frequency is 0.41 dB. For antenna B after changing Feeding Point Position bandwidth of First Band of 
this patch antenna is 49 MHz and a center frequency 2360 MHz, bandwidth of Second Band of this patch antenna is 95 
MHz and a center frequency 3081 MHz and bandwidth of Third Band of this patch antenna is 60 MHz and a center 
frequency 3970 MHz are obtained. For antenna C after changing Patch Position, bandwidth of First Band of this patch 
antenna is 46 MHz and a center frequency 2378 MHz, bandwidth of Second Band of this patch antenna is 92 MHz and a 
center frequency 3086 MHz and bandwidth of Third Band of this patch antenna is 60 MHz and a center frequency 3976 
MHz are obtained. 
 
REFERENCES 
 
[1]. James, J.R. and Hall, P.S.: „Handbook of Microstrip Antennas‟ (Peter Peregrinus). 
[2]. Constantine A. Balanis : „Antenna Theory, Analysis and Design‟ (John Wiley & Sons). 
[3]. Lu JH, Tang CL, Wong KL, „Novel dual-frequency and broadband designs of the slot-loaded equilateral Triangular 
Microstrip Antenna‟ IEEE Trans. Antennas Propag. 2000;48;1048-54. 
[4]. Row JS. „Dual-frequency triangular planar inverted-f Antenna‟ IEEE Tran Antennas Propag 2005;53;874-6. 
[5]. Kai-Fong Lee, Kwai- Man Luk, Jashwant S. Dahele, „Characteristics of the Equilateral Triangular Patch Antenna ‟  IEEE 
Tran. Antennas Propag.1988;36;1510. 
[6]. C. L. Mak, K. M. Luk, K. F. Lee, „Wideband Triangular Patch Antenna‟ IEE. Proc. Microwave Antennas Propag. 1999. 
[7]. Shan-Cheng Pan and Kin- Lu Wong, „ Dual Frequency Triangular Microstrip Antenna with Shorting Pin‟ IEEE Tran. 
Antennas Propag.1997;45;1889. 
[8]. D.M. Pozar and D. H. Shaubert, „MicrostripAntennas : The Analysis and Design of  Microstrip Antenna and Array‟ IEEE 
Press,Inc., 1980. 
[9]. I. J. Bahl and P. Bhartia, „Microstrip Antennas, Artech House, Dedham, MA, 1980. 
[10]. Ansoft Designer, www.ansoft.com. 
[11]. IE3D [1] by Zeland software Inc.. 
 
 


Multibanding of Microstrip Patch Antenna by Feeding Point and Patch Position

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Multibanding of Microstrip Patch Antenna by Feeding Point and Patch Position

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