International Journal of Engineering Trends and Technology (IJETT) – Volume 17 Number 3 – Nov 2014
Performance Improvement of Dual U-Slot Microstrip
Patch Antenna Using Frequency Selective Surface
with Modified Jerusalem Cross Elements
Poorwa Bhagat#¹ Prof. Prashant jain*²
#M.E., Department of Electronics and Communication
Jabalpur Engineering College Jabalpur M.P. (482011) India
ABSTRACT — Dual U-slot microstrip patch antenna using
FSS (frequency selective surface) with modified Jerusalem
cross element is presented in this paper. Two U slots are
designed on rectangular patch and fed through microstrip
line, using FSS with modified Jerusalem cross elements
proposes a new antenna in multi band operation within 1
GHz to 10 GHz and improve the antenna gain and return
loss characteristic. It is demonstrated through simulation
that the return loss value occurred at 2GHz, 2.27GHz,
2.54GHz, 3.27GHz, 4.45GHz, 5.45GHz, 6.27GHz, 6.9GHz,
8.72GHz, and 9.54GHz respectively for mobile
satellite(earth to space communication), earth exploration
satellite (space to earth)(space to space), fixed
satellite(space
to
earth
communication),
radio
location(radio
navigation
service),
fixed
mobile(aeronautical mobile telemetry for flight testing by
aircraft stations), Earth exploration-satellite service,
aeronautical Radio navigation service to airborne radars,
fixed
satellite
service
(Earth-to-space
communication)(space-to-Earth communication), radio
location and space research applications. The proposed
antenna is analysed using Ansoft HFSS 13 and simulated
results are presented in terms of return loss, VSWR,
percentage bandwidth and radiation pattern. The
performance of the antenna has been analysed by using
FSS consisting of Jerusalem cross element which is used to
improve antenna performance with sufficient bandwidth
and comparatively high return loss than dual U slot
without FSS and is capable of multi band operation.
Key word — FSS, Jerusalem cross element, return loss, dual Uslot patch antenna, multiband operation.
I. INTRODUCTION
Microstrip patch antenna has many advantages such as small
size, light weight, cost effective and compatibility with
integrated circuit technology operating in multiple bands [1].
For wireless communications, multi band and wide band patch
antennas will be required for accurately transmitting the voice,
ISSN: 2231-5381
data, video and multimedia information in wireless
communication systems, such as ultra wide-band
measurement applications, wireless local area networks,
Global Positioning system services, radio-frequency
identification applications[2]-[3]. Most serious problem of a
patch antenna is its narrow bandwidth because a patch on a
dielectric substrate has surface wave losses. The surface wave
will reduce antenna efficiency, gain and bandwidth. To
enhance the bandwidth and frequency bands of a patch
antenna, FSS is used having a phenomenon with high
impedance surface that reflects the plane wave in phase and
suppresses the surface wave [4]. A FSS consisting of regular
Jerusalem cross element was first used to study its impact on
the bandwidth and resonant frequencies of U slot patch
antenna., another FSS with modified Jerusalem cross elements
was proposed to improve the bandwidth, antenna gain and
return losses of dual u slot patch antenna. The FSS has a
variety of applications in antennas, spatial microwave and
optical fiber, absorbers, polarisers, planer materials, and
artificial magnetic conductors (AMC) designs [5]-[7]. Multi
band microstrip patch antennas are used in many wireless
communication services such as GSM, CDMA, DCS and PCS
[2, 3]. A Frequency Selective Surface (FSS) is comprised of
an infinite array of periodically arranged metallic patch or
aperture elements that exhibit total reflection or transmission
of microwaves, respectively [8]. Typical FSS geometries are
designed by dipoles, rings, square loops, fractal shapes etc.
The impact of a FSS on patch antenna performance depends
on the lattice geometry, element periodicity, and the electrical
properties of the substrate materials. The transmission or
reflection characteristic of a FSS depends on the shape, size,
periodicity, and geometric structure of FSS element.
This paper focuses on dual U slotted patch antenna using
frequency selective surface with jerusalem cross element to
achieve multi band operation. This is an extension of previous
work taking [9] as reference paper presented Dual U slot
MPA. In this paper I have modified the design using FSS with
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International Journal of Engineering Trends and Technology (IJETT) – Volume 17 Number 3 – Nov 2014
modified Jerusalem cross element to achieve multi band
operation with increased return loss and fractional bandwidth.
In this paper two different size U slot are used which are
connected via a bridging element and frequency selective
surface is used with modified Jerusalem cross element in
between two substrates. The proposed antenna is designed
using FR4 substrate for upper and lower dielectric substrates,
having dielectric constant of 4.4 and thickness of upper and
lower dielectric substrate is kept at 1.6 and 2.8mm
respectively. It is fed by a 50Ω microstrip transmission line.
Various attempts are made to adjust the height of upper and
lower dielectric substrate, and the width of feed line. The
proposed antenna design is able to operate in the frequency
band of 1 to 10 GHz having ten resonance frequency which
covers most of the desired communication band. The
parameter of the antenna such as return loss, percentage
bandwidth, VSWR and gain are varies for different height and
width are also discussed in paper.
Where
ƒₒ= resonance frequency
c = speed of light
w = width of patch
ℇr= relative dielectric constant
Fig 2 shows the regular Jerusalem cross element and its
dimension are W1=0.5 to 2mm (width of the vertical or
horizontal end loading), W2=0.5 to 3mm (width of the crossdipole), L1=7 to 10mm (length of the vertical/horizontal end
loading), L2=12 to 14mm (length of a Jerusalem cross
element), and P=16mm (periodicity). The FSS constructed
with regular Jerusalem cross element is used to increase the
antenna performance. Based on this regular cross element, a
modified Jerusalem cross element is designed as shown below
in fig.3, which consists from regular elements, Which is used
as FSS in this MPA to enhance antenna performance. The
dimension of this is shown in table 1.
Fig.2 Details of regular Jerusalem cross element
Fig.1 Dual U slot patch antenna without FSS and its dimension
II. ANTENNA GEOMETRY AND DESIGN
The designed antenna consists of ground plane, FR4 substrate
material, FSS with Jerusalem cross element, dual U slot patch
and microstrip feed line. The height h of substrate using FR4
substrate material with dielectric permittivity (ℇr) of 4.4 is
4.4mm and is fed by 50Ω microstrip transmission line. The
simulation of the proposed dual U slot patch antenna using
FSS is performed using Ansoft HFSS version 13 simulator.
Figure 1 shows the dual U slot patch antenna and its
dimension, in which a patch having width and length of 40mm
and 47mm, in which two U slots of different dimension and a
bridging element which connects this two U slots. In the
proposed antenna designed parameters are selected based on
the transmission line model [1]. The resonant frequency is
given by
Fig.3 Modified Jerusalem cross element and its dimensions
ƒₒ =
ISSN: 2231-5381
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International Journal of Engineering Trends and Technology (IJETT) – Volume 17 Number 3 – Nov 2014
Table1. Parameters of modified jerusalem cross frequency selective surface
Parameters
gives six bands below 10 dB and maximum return loss is 31.5dB at frequency of 7.9GHz having 523.4MHz bandwidth..
Value(mm)
W1
1
W2
1.25
W3
L1
L2
0.5
11
11
L3
L4
14
26
Table 2 maximum return loss and bandwidth due to different substrate height
Substrate
Heights(mm)
1.6 and 2.8
Maximum Return
Loss(dB)
-31.51
Maximum
Bandwidth(MHz)
523.4
1.2 and 3.2
2.2 and 2.2
-27.05
-23.39
521.8
584.5
2.0 and 2.4
-35.43
516.5
Based on this modified Jerusalem cross element, dual U
slot patch antenna is designed using FSS as shown in the fig.4 shown
below, and by changing the height of two substrates and feed width
result is analysed.
Fig.5 comparison due to change in different substrate height
B. Variation in width of feed line
Fig.4 Designed dual U-slot microstrip patch antenna using FSS with
Jerusalem cross element
III. PARAMETRIC STUDY
The simulation study of the proposed Antenna is done using
commercial software package HFSS version 13. Comparisons
of simulation results of return losses for the Dual U-slot patch
antenna implanted with and without a FSS are studied. This
section presents how the parameters of antenna such as return
loss and frequency changes with respect to change in change
in substrate height and feed width with using FSS, and
comparison result of Dual U slot patch antenna without using
FSS and with FSS.
Initially the width of feed line is 2mm, width of feed is tuned
to get the best result of Dual U slot microstrip patch antenna
with FSS i.e. multiband operation and improved return loss.
We got the best desired result of Dual U-slot microstrip patch
antenna when feed width is 6mm using FSS with Jerusalem
cross element i.e. more no. of bands between 1 to 10 GHz
having maximum return loss of -36.71dB and maximum
bandwidth of 647.3MHz between band of 5.14 to 5.78GHz.
A. Variation in substrates heights
The height h1 and h2 of substrate is tuned to understand the
effect of variation on antenna return loss and multi bands. The
results are summarized in table 2 below and comparison is
shown in fig.5 shown below. The total substrate height is
tuned to 4.4mm, when the upper and lower substrate height is
set as 1.6 and2.8 we get the satisfactory performance, that
ISSN: 2231-5381
Fig.6 comparison due to change in microstrip feed line width
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International Journal of Engineering Trends and Technology (IJETT) – Volume 17 Number 3 – Nov 2014
IV ANTENNA SIMULATION RESULT
This section describes the simulation results of proposed
dual U slot microstrip patch antenna with FSS.
Comparison on result is also shown with dual U slot
MPA with FSS and without FSS. Fig.7 shows the
simulated return loss of proposed antenna and dual U slot
MPA without FSS. It is noticed that ten resonant
frequencies occurred in the range 1 to 10 GHz which are
2.0GHz, 2.27GHz, 2.54GHz, 3.27GHz, 4.45GHz,
5.45GHZ, 6.27GHz, 6.90GHz, 8.72GHz and 9.54GHz
having return losses of -17.37dB, -13.83dB, -20.56dB, 18.67dB, -31.78dB, -22.75dB, -18.74dB, -20.73dB, 36.71dB and -17.19dB respectively.
Fig.7 comparison of return losses of dual U-slot patch antenna
with using FSS and without using FSS
Fig.8Shows the simulated VSWR of dual U slot microstrip
patch antenna with FSS. It is observed that VSWR for this
multi band antenna is 1.31 at 2.0GHz, 1.51 at 2.27GHz, 1.20
at 2.54GHz, 1.52 at 3.27GHz, 1.17 at 4.45GHz, 1.20 at
5.45GHz, 1.34 at 6.27GHz, 1.39 at 6.90GHz, 1.02 at 8.72GHz
and 1.32 at 9.54GHz. Ideally, the VSWR should be below 2
[5]. The antenna will operate for the frequencies where value
of VSWR is less than 2. Fig.8 shows that VSWR is below 2
wherever the Sıı at the desired working frequencies is less
than -10 dB.
Fig. 8 VSWR of the proposed Antenna
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Fig. 7 shows the simulated result of proposed antenna,
Bandwidth at each resonant frequency for this proposed
antenna can also be seen. The proposed antenna’s maximum
bandwidth are 921.7MHz at 9.54GHz and 647.5MHz at
5.45GHz frequency band, Table shown below shows the
bandwidth and percentage bandwidth of proposed antenna.
Table 3 simulation result of proposed dual u slot microstrip patch antenna
with FSS
Resonating
frequency
(GHz)
2.0
Return
loss
(dB)
-17.37
Bandwidth(MHz)
VSWR
Gain
(dB)
161.5 (8.07%)
1.31
30.21
2.27
-13.83
112 (4.93%)
1.51
7.39
2.54
3.27
-20.56
-18.67
205.6 (8.09%)
212 (6.49%)
1.20
1.52
8.94
0.26
4.45
5.45
-31.78
-22.75
193.8 (4.35%)
647.5 (11.88%)
1.17
1.20
2.22
6.01
6.27
6.90
8.72
9.54
-18.74
-20.73
-36.71
-17.19
377.4 (6.01%)
538.2 (7.8%)
465.9 (5.34%)
921.7 (9.66%)
1.34
1.39
1.02
1.32
4.59
5.88
20.51
6.25
Antenna gain is the ratio of radiation intensity in a given
direction to the radiation intensity of an isotropic antenna.
gain at different resonation frequency is given in the table and
the radiation pattern showing gain and directivity is shown in
fig.9 shown below.
Ø=90°
(a) at 2GHz
Ø=90°
(c) at 2.54GHz
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Ø=90°
(b) at 2.27GHz
Ø=90°
(d) at 3.27GHz
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International Journal of Engineering Trends and Technology (IJETT) – Volume 17 Number 3 – Nov 2014
Ø=90°
(e) at 4.45GHz
Ø=90°
(g) at 6.27GHz
Ø=90°
(j) at 8.72 GHz
Ø=90°
(f) at 5.45GHz
(c)At 2.54GHz
Ø=90°
(i) at 6.90GHz
(d) at 3.27 GHz
(e) at 4.45 GHz
(f) at 5.45 GHz
(g) at 6.27 GHz
Ø=90°
(k) at 9.54GHz
(h) at 6.90 GHz
Fig.9 simulated gain and directivity at resonating frequencies
Fig. 10 shows the 3D radiation pattern of designed antenna
to understand the behavior of antenna. Stable radiation pattern
are obtained which suggests good antenna performance.
(i)at 8.72 GHz
(j) at 9.54 GHz
Fig. 10 3D radiation pattern at resonating frequencies
V. CONCLUSION
.
(a)
At 2 GHz
ISSN: 2231-5381
(b) at 2.27 GHz
In this paper, a multi band antenna with dual u slot using FSS
with modified Jerusalem cross element is designed and
simulated. The proposed antenna is simulated on HFSS 13
version. The simulated result shows that designed antenna
structure is suitable to operate at ten frequency bands i.e.
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International Journal of Engineering Trends and Technology (IJETT) – Volume 17 Number 3 – Nov 2014
2GHz, 2.27GHz, 2.54GHz, 3.27GHz, 4.45GHz, 5.45GHz,
6.27Ghz, 6.90GHz, 8.72GHz, 9.54GHz having return loss of 17.37dB, -13.83dB, -20.56dB, -18.67dB, -31.78dB, -22.75dB,
-18.74dB, -20.73, -36.71dB, -17.19dB respectively. The
proposed designed is useful for radio navigation service, fixed
mobile application, Earth exploration-satellite service,
aeronautical Radio navigation service to airborne radars.
ACKNOWLEDGEMENT
This research paper is made possible through the help and
support from everyone including: parents, teachers, friends,
and in essence, I would like to thank my guide prof. Prashant
Jain sir. The product of this research paper would not be
possible without all of them.
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ISSN: 2231-5381
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