Download 2 Analysis of rectangular microstrip patch antenna by cavity model

DESIGN & ANALYSIS OF ORTHOGONAL CUTTING SLOT
MICROSTRIP PATCH ANTENNA AT 2.0 GHz FOR DUAL BAND
APPLICATION
Priyanka sikarwar1(M.E), Rachit Jain2(Assistant Professor)
[email protected], [email protected]
ITM College Gwalior M.P. (india), ITM College Gwalior M.P. (india)
Abstract- In this paper, we designed a
orthogonal cutting slot patch antenna for
dual band application. After designing
the antenna on 2 GHz , we study and
analyzed the results of simulated
antenna. For wireless and WLAN-band
because of antenna has dual band, we
uses the dielectric substrate 4.4, loss
tangent 0.002 and having the substrate
height 1.6 mm.
The simulation of
antenna on IE3d software at 2 GHz
frequency showing the bandwidth 23%
and 53.38% having return loss -37db and
-30db,antenna resonant at frequency 1.5
GHz and 2 GHz . Results i.e., return loss,
VSWR, smith chart, gain, directivity,
efficiency and 3D-radiation pattern and
also 2D radiation pattern of antenna for
software design are shown.
Keywords- Orthogonal, cutting slot,
microstrip antenna, IE3D software,
enhances bandwidth.
1 Introduction
Microstrip patch antennas are a very important
component of communication systems, by
definition, an antenna is a device used to
transform an RF signal, traveling on a conductor,
in to an electromagnetic wave in free space the
broadband circularly polarized microstrip
antennas play a vital role in wireless
communication due to its low-profile, smallsize and light weight. As well as to the fact that
they are simple to manufacture, suited to
planar and non planar surfaces, mechanically
robust, easily integrated with circuits, allow
multifrequency operation to be achieved [1].
However, their further use in specific systems
is limited because of their relatively narrow
bandwidth. In principal, wide bandwidth of
microstrip patch antennas or bandwidth
enhancement can be achieved by several
efficient approaches [2]. In this paper, coaxial
feed techniques are applied to the rectangular
microstrip patch antenna. Because coaxial feed
is a widely used one. The inner conductor of
coaxial cable is connected to the radiating
patch and the outer conductor is connected to
the ground plane. This feed is also easy to
match and it has low spurious radiation by
using teflon conector. The advantage of this
feed is that it occupies less space than the
other feeds [3]. Microstrip antenna is one of
these kinds of antenna with low section, panel
structure of typical model, which develops
with the request of modern communication
development. There are many methods to
discuss the electromagnetism radiation
characteristic of the antenna.
2 ANALYSIS OF RECTANGULAR
MICROSTRIP PATCH ANTENNA BY
CAVITY MODEL
Rectangular patch antennas can be
designed by using a cavity model [5] suitable
for moderate bandwidth antennas. The lowestorder mode, TM10, resonates when the
effective length across the patch is a halfwavelength. “Fig.1”, demonstrates the patch
fed below from a coaxial along the resonant
length. Radiation occurs due to the fringing
fields. These fields extend the effective open
circuit (magnetic wall) beyond the edge.
A. Resonance frequency of antenna
The resonance frequency f mn depends
on the patch size, cavity dimension, and the
filling dielectric constant, as follows:
f mn 
kmn
k mn c
2
velocity of light,  r is the dielectric constant
of substrate, and
 m   n 
k mn  
 

W   L 
W
 2l
(5)
constant and l = line extension which is
given as:
1
 eff


 r  1  r  1 
h 2


1  12
2
2

W 
(6)
( 2)
l
 0.412
h

eff

eff
W

 0.3  0.264 
h

W

 0.258  0.8 
h

(7)
B.
c
2 fr  r
c
fr
2 f r  eff
2
For TM01 mode, the length of nonradiating rectangular patch’s edge at a certain
resonance frequency and dielectric constant
according to equation (1) becomes
L
c
Where  eff = effective dielectric
(1)
r
where m = 0, 1, 2, and n = 0, 1, 2…,
= wave number at m, n mode, c is the
2
L
2
r 1
(3)
(4)
Cavity field of antenna
From the cavity model explained
above, the electric field is assumed to act
entirely in the z-direction and to be a function
only of the x and y coordinates i.e.
E  ZˆEZ x, y 
(8)
Where f r = resonance frequency at
which the rectangular microstrip antennas are
to be designed. The radiating edge W, patch
width, is usually chosen such that it lies within
the range L<W>2L, for efficient radiation. The
ratio W/L = 1.5 gives good performance
according to the side lobe appearances.
In practice the fringing effect causes
the effective distance between the radiating
edges of the patch to be slightly greater than L.
Therefore, the actual value of the resonant
frequency is slightly less than fr. Taking into
account the effect of fringing field, the
effective dielectric constant for TM01 mode is
derived using [6,7]
By using above equation we can find
the value of actual length of the patch as,
The z-component of the electric field Ez
satisfies the two-dimensional wave equation
 2   2 

 k 2   0
x 2
y 2
(9)
The outward current flowing on the
perimeter of the patch must be zero (since the
patch boundary is an open-circuit). So
E 
0
n
(10)
Where n is the outward normal vector
at the perimeter of the patch by using the
separation of variables, the electric field of the
m and n mode numbers [9] is
 mx  ny 
     Cos


 W  L 
(11)
C.
Far field of antenna
For calculate the far field, the aperture
model is used. The resonator surface is
considered to be a set of four slots of width
[8]. By using Green's function the following
general form of the far field for any (m, n)
mode
r  
Fig.1: Coaxial feed microstrip patch antenna
jke jkr
i  x cos    y sin   i   x sin  cos    y cos  cos  
2r

 

3.Calculation of the ground plane
dimensions ( Lg and Wg ):
(12)
Where





 W
 W 
m
m
 x    1   1 j sin  
  1   1 cos 

 2
 2 


L
 L n 
 L n
n
sin ca  j n sin c 
   1 sin c 
2
2 
2
 2
 2

h 



(13)
and





 L
 L 
n
n
 y    1   1 j sin    1   1 cos 
 2
 2 

h 0

W
 W m
sin ca  j m sin c 

2
2
 2


 W m 
m

   1 sin c 

2 

 2
(14)
Then the far field components are
 
 
jke jkr
 x cos    y sin  
2r
(15)
jke jkr
  x sin  cos   y cos  cos  (16)
2r
Ideally the ground plane is assumed
of infinite size
in length and width
but it is practically
impossible to
make a such infinite size
ground
plane, so to calculate the length and
width of a ground plane followings
Equations are given as:
Lg = L + 6h
Wg = W + 6h
Coaxial probe type feed is
to be used in this design. The center of
the patch is taken as the origin and the
feed point location is given by the coordinates (Xf , Yf) from the origin. The
feed point (X=42.8mm,Y=4.8mm )
must be located at that point
on the
patch, the resonant frequency for the
antenna for dual band are 1.5GHz and 2
GHz .
Antenna Design on IE3d software
Where  = k sin  cos  , =
k sin  sin  , k 
2
0
, and 0 = wavelength
in free space.
Equation (12) enables one to plot the
radiation pattern for every mode of the
rectangular microstrip patch antenna.
Fig. 2: Geometry of Proposed antenna on IE3D
Antenna Design on Hardware
Feeding method
feedPoint
(Probe feeding)
(x=42.8mm,y=4.8mm )
Width of the ground
55.6mm
(Wg)
Length of the
47.6mm
ground (Lg)
Width of the patch
46mm
(Wp)
Length of the patch
38mm
(Lp)
Fig. 3: 3D view of Proposed antenna on IE3D
Table .1: different parameter of antenna used in
designing
4. RESULTS OF SIMULATE DESIGN
Design of Micro
strip patch
antenna
Design on
Software base
antenna
Name of Pattern
Orthogonal
Frequency of Operation
2.0
After simulating the proposed antenna
design on IE3d simulator, we get various
results. All these various results are shown
below. Firstly we shown & discuss all the
results of proposed antenna design on IE3d
software.
4.4
Simulation results using IE3d
Software
(GHz)
Dielectric constant of
substrate
Loss tangent
.002
Height of the dielectric
1.6 mm
substrate (mm)
Fig. 4: Return loss Vs frequency
Fig. 5: VSWR Vs Frequency
Fig. 8: Antenna Directivity Vs Frequency
Fig. 9: Antenna and radiation Efficiency
Fig. 6: Smith chart of impedance matching
Fig. 10: 3D radiation pattern of antenna
Fig. 7: Antenna gain Vs Frequency
Table: 2 bandwidth of dual band
Antenna
Design
Bandwidth
(%)
Return
Loss (dB)
1st
23%
-37
2nd
53.38%
-30
REFERENCES
Fig. 11:2D radiation pattern of antenna
[1]Thomas A. Milligan “2nd addition
Modern antenna design”pp: 318-354 .
[2]POZAR D.M., and SCHAUBERT D.H.,
“Microstrip Antennas, the Analysis and
Design of Microstrip Antennas and
Arrays”, IEEE Press, New York, USA,
1995
[3]Bahl, I.J. and Bharatia, P. Microstrip
Antennas, Artech House, 1980.
[4]D. M. Pozar, “Microstrip antennas”,
IEEE Proc., vol. 80, pp. 79-91, January
1992.
Fig. 12: Axial Ratio Vs Frequency of antenna
5. CONCLUSION
Microstrip antennas have become a rapidly
growing area of research. Their potential
applications are limitless, because of their
light weight, compact size, and easy of
manufacturing.
In our paper, we have design and
analyzed the orthogonal cutting slot Shape
Microstrip Patch antenna on 2 GHz dual
band having the band width of 23% and
53.38%. The proposed antenna designs have
been analyzed between 1GHz to 3GHz.
The proposed antenna is designed on a
GLASS EPOXY material Substrate having
dielectric constant 4.4, loss tangent .002.
[5]Mohammad A.A.,Subhi H. ,Ahmad A.K.
and Juma S.M. “Cavity model analysis of
rectangular microstrip antenna operating
in TM03 mode”.IEEE Trans. Antenna and
Propagation,vol.2.pp.2218-2223,Februry
2006.
[6]G. P. Gauthier and G. M. Rebeiz,
"Microstrip antennas on synthesized low
dielectric-constant substrates," IEEE
Trans.Antennas Propagat., vol. 45, no. 8,
pp 1310-1313, 1997.
[7]K. R. Carver and J. W. Mink,
"Microstrip antenna technology," IEEE
Trans Antennas Propagat., vol. AP-29,
no.1, pp 2-23, 1981.
[8]P. Hammer, D. V. Bouchaute,
D.Verschraeven, and A. V. Capelle,"A
model for calculating the radiation field of
microstrip antennas," IEEE Trans.
Antennas Propagat.vol. AP-27, no.2, pp
267-270, 1979.
[9] C.A. Balanis, Antenna Theory and
Design, John Wiley & Sons, 1997.
[10] Rezaul Azim, Ahmed Toaha
Mobashsher, Mohammad Tariqul Islam
and Norbahiah Misran, “Compact planar
antenna for UWB applications,” IEEE
ICMMT, 2010
[11] mohamaed Nabil Srifi, Symon K.
Podilchak, Mohamed Essaaidi, and Yahia
N. N. Antar, “A planar circular disc
monopole antennas using compact
impedence matching networks for ultra
wide band (UWB) applications,” IEEE
Trans. Antennas Propag., pp. 782-785,
2009.
[12]
S. Cumhur Basaran, “Dual
wideband CPW fed split ring monopole
antenna for WLAN applications,” 177,
2010