International Journal of Engineering Trends and Technology (IJETT) – Volume 16 Number 2 – Oct 2014
Comparative Analysis of Microstrip Patch Antenna
using EZNEC and ADS
Puthanial.M#1 , Shubhashini.R*2, Pavithra.K#3, Priyanka Raghu#4 , Dr. P. C. Kishore Raja#5
Saveetha School of Engineering, Saveetha University
Abstract— There is a huge increase in design of various wireless
antennas for daily and commercial use. They are designed with
various specifications. After deeply analyzing the comparisons,
this paper is a result of comparison of two designs, namely micro
strip patch antenna at 2.4GHZ using EZNEC and another micro
strip patch antenna at 10.65GHZ using ADS. This comparison
differentiates the results based on directive gain and other
parameters..
surface of the patch antenna are both in +y direction, thus they
add up in phase and produce the radiation of the antenna. The
raise in radiation from the fringing fields is due to the
advantage in voltage distribution. Because, the current adds up
in phase and also there is an equal current but with opposite
direction in ground plane which cancels the radiation.
Keywords— Micro strip patch antenna, ADS, EZNEC,
Directivity, Power gain, Beam width, Radiation pattern.
I. INTRODUCTION
Patch antenna is a wafer like directional antenna suitable
for covering single floor, small office; small stores and other
inter locations where access point cannot be placed centrally.
Patch antenna produce the hemispherical coverage, spreading
away from the mount point at a width of 30-180degree.
Patch antenna also known as planar, slap planar or micro
strip antennas. They are formed by overlying two metallic
plates, one larger than the other, with dielectric sheet in the
middle. This type of antenna is usually encased in black
plastic or white plastic, not only to protect the antenna but also
to make it easy to mount because they are flat , thin and light
weight, patch antenna are often hung on walls of ceilings
where they virtually cursive and blend easily into the
background. The patch conducting in micro strip antenna may
have planar or non-planar geometry.
II. ANTENNA STRUCTURE AND DESCRIPTION
The micro strip patch antenna is composed of dielectric
substrate on one side with ground plane on other side. The
rectangular micro strip antenna is the most commonly used
one, which has a one-half wavelength long section along the
transmission line. The antenna generally has two slots.
When the antenna substrate is air, the rectangular micro
strip antenna has one-half of a free space wavelength. When
the substrate is loaded with dielectric, the length of the
antenna decreases as the relative dielectric constant of the
substrate increases.
The rectangular micro strip antenna has a virtual shorting
plane along its centre, which can also be replaced with a
physical shorting plane to create a quarter wavelength micro
strip antenna , which is sometimes called half patch. The
resonant length of the antenna is short(slightly) because of
extended electric fringing fields. It is the fringing fields that
are responsible for radiation. The fringing fields near the
ISSN: 2231-5381
Figure 1: Micro strip patch antenna and Electric field lines
Figure 2: Basic form of Patch antenna
III. BACKGROUND
The rectangular patch antenna has the most two models.
They are the transmission line model and the cavity model.
The transmission line model has few short comings that it
does not support transverse electric – magnetic (TEM) mode
of transmission as phase velocities would be different in
substrate and air.
The cavity model provides a better modelling of radiation
pattern and is closer in the physical interpretation of the
characteristics of the antenna. This cavity model helps to find
the normalized fields within the dielectric more accurately by
treating the region as a cavity bounded by electric conductors
(above and below) and by magnetic walls along the perimeter
of the patch antenna..
IV. SIMULATION TOOLS
EZNEC
•EZNEC is a electromagnetic (EM) field simulator for 3D
modeling that takes advantage of the familiar Microsoft
Windows graphical user interface.
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International Journal of Engineering Trends and Technology (IJETT) – Volume 16 Number 2 – Oct 2014
•S Parameters, Resonant Frequency, and Fields can be
calculated using this software.
•Its basic mesh element is in the shape of tetrahedron which
helps users to develop variety of shapes and curves in its 3D
modeling window.
•In 3D modeler window we create the model geometer
•Antennas are used in a vast variety of applications, and
thus take come in a vast variety of form factors and radiation
mechanisms. The range of simulation methods in EZNEC
allows the engineer to choose the best technique for each
application.
ADS
Advanced Design System (ADS) is electronic design
automation software which helps designers to design RF
electronic circuits, and has application in microwave, and high
speed digital circuits. It supports every step of design process
of an antenna (for example). It is complete, integrated set of
fast, accurate and easy to use system. It helps designers to
view 3D structure of antennas.
Edge feed width
<2nm
Edge feed length
>20nm
III. SIMULATION AND DESIGN RESULTS
EZNEC
By analyzing the simulation and design results in EZNEC,
the structure of patch antenna elements consisted of dielectric
substrate in one side and ground planar on the other side. The
beam width was 40 degrees in E- plane and 26 degree in
magnetic field plane. The return loss which is the loss of
power in radiation returned and reflected by discontinuity in a
transmission line was found to be varying between 2.24GHZ
to 2.5GHZ. Its value at 2.24 GHZ is -18.75db and 12.2dB at
2.4GHZ.
V. DESIGN CONSIDERATIONS
I.SIMULATION STUDIES BY ADS
By analyzing the simulation studies by ADS, the TM10
mode is considered in it. In this three field components has
been considered. The electric field in Z direction and
magnetic field o-components in X and Y direction using
Cartesian co-ordinate system, where X and Y axis is parallel
with the ground-plane and Z axis is perpendicular. The
electric field variation is considered negligible in Z axis, and
so it is omitted. This simulation is based on cavity model.
II. DESIGN AND SIMULATION USING EZNEC
By analyzing the design and simulation using EZNEC, the
following things have to be determined for design of a patch
antenna.
€reff = Effective dielectric constant
€r = Dielectric constant of the substrate.
h = Height of dielectric substrate
W = Width of the patch
L= Length of the patch.
Figure 3: Radiation pattern of patch antenna in EZNEC(3D
view)
The following calculations were also carried out for designing
the micro strip patch antenna using EZNEC
Solution frequency
2.4GHZ
Patch dimension of X
40- 41nm
Patch dimension of Y
40- 41nm
Substrate dimension along X
82-84nm
Substrate dimension along Y
172-173nm
Figure 4: Radiation pattern of patch antenna in EZNEC
(Normal view)
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International Journal of Engineering Trends and Technology (IJETT) – Volume 16 Number 2 – Oct 2014
ADS
The equivalent circuit of micro strip patch antenna at 10.65
GHZ was simulated by giving various parameters like
resistance(R), capacitance(C), impedance(Z), frequency(F) as
inputs to the feed line. The feed line are connected with the
individual equivalent circuit to obtain the overall schematic.
The directivity of an antenna is generally expressed in decible .
The directivity of an antenna is equal to the ratio of maximum
power density to its average value over the sphere as observed
in franhoufer zone of an antenna.
The radiation pattern obtained from simulation by ADS
estimates that it has resulted in a directivity of 3 db. Generally,
the fringing fields at the radiating edges can be viewed as two
radiating slots above the ground plane.
By assuming that all radiations occur in one half of the
hemisphere. The patch’s radiation at the fringing fields has
Figure 6: Radiation pattern of patch antenna in
resulted in a certain far field radiation pattern. This case is
ADS(Normal view)
often described as front to back ratio.
In practical cases, this Front- to – back ratio depends on
SUMMARY
ground- plane size and shape. Since there are two slots,
another 3 db were added. These slots were taken typically to
Dr. P.C Kishore Raja, Professor and Head, electronics and
have length according to y-axis. Such a plot has a gain about 2 Communication Engineering Department, Saveetha School of
to 3 d B. Thus the total gain resulted was 8 to 9 d B. The 3 d Engineering, Saveetha University, Chennai
B angular width is twice the angle with respect to the angle of
Puthanial. M is pursuing her PhD in Wireless
maximum directivity.
communication related work in the area of smart antennas
under the guidance of Dr.P. C. Kishore Raja, Professor and
VI. CONCLUSIONS
Head, Department of Electronics and communication who
A single patch antenna provides a maximum directive gain completed his Doctorate from Anna University.
of around 6-9 d B. This comparative study of simulation and
Shubhashini.R, Pavithra.K and Priyanka Raghu,
design of micro strip patch antenna has produced a result of Undergraduate students from electronics and communication
10.65GHZ which was simulated using ADS and 2.4 which department worked closely on the paper and currently
was designed using EZNEC of frequency. And the gain working on their projects using softwares- EZNEC, ADS and
obtained was 11.64 d B (using EZNEC) and 8-9 d B (using HFSS.
ADS).
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ISSN: 2231-5381
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