1
The Wideband Circular Microstrip Patch Antenna (WCMPA)
with Round Bottom Flask (RBF) Shape Etched Ground Plane for
Wireless Applications
1
1,2
Halappa R. Gajera, 2Anoop C.N
Dept. of Electronics, Post Graduate Centre, Hemagangothri, University of
Mysore,
Hassan, Karnataka, -573220, India,
E-mail: haleshn@rediffmail.com, anoopappu2008@yahoo.co.in,
Abstract- in this paper, we propose a
design of circular microstrip patch
antenna (CMPA) with a round bottom
flask shape etched ground plane. This
ground plane improves the bandwidth,
impedance matching and the relocation
of resonant frequency to make the
compact CMPA. The size reduction of
about 40.37% compared to the actual
area required to resonate at 5.5GHz.
The bandwidth 760MHz with respect to
center frequency 5.48GHz which covers
wireless bands such as HPERLAN/1 and
HIPERLAN/2 bands. The percentage
bandwidth of 13.86 and the average gain
of 3.5dBi are achieved.
(ETSI) High Performance Local Area
Network type 1 (HIPERLAN/1), and High
Performance Local Area Network type 2
(HIPERLAN/2) which uses the frequency
bands 5.150 GHz– 5.350 GHz and 5.470
GHz 5.725 GHz[1].
Index Words: CMPA, CCMPA, DGS,
Dielectric, HPERLAN/1, HIPERLAN/2
WLAN, etc.
1.
INTRODUCTION
The need for wireless broadband
communications has increased rapidly in
recent years demanding quality of service,
security,
handover,
and
increased
throughput for the wireless local area
networks (WLANs). The most important
high-data-rate
wireless
broadband
networking systems for next generation
Fig 1 (a) The top view of ground plane with
wireless communications are European
round bottom flask shaped slot, (b) Top view of
Telecommunications Standards Institutes
CMPA, (c) Side view of CMPA.
2
The modern wireless communication
systems require the antennas for different
systems and standards with characteristics
like compact, broadband, multiple resonant
frequencies and moderate gain. Because of
many attractive features, microstrip patch
antennas
have
attention
for
received
wireless
considerable
communication
applications [2–8]. Single layer microstrip
antennas have very narrow bandwidth, but
using
two-layer
proximity
coupled
microstrip antennas higher bandwidth can
be achieved [9–13]. Since radiation pattern
II. ANTENNA DESIGN
The antenna is fabricated on the substrate
FR4_epoxy with relative permittivity εr =
4.4 and the thickness of 3.2mm. The radius
of the patch (a) and ground plane are
calculated using the formulas given in [1],
for the resonant frequency of 5.4GHz. The
actual radius of patch as per formula is
7.12mm; we reduced the radius of the
patch to 5.5mm so the size of the CMPA is
reduced by 40.37% because of round
bottom flask shape etched on the ground
plane.
of a microstrip antenna has wide beam
width in one hemisphere, two back-to-back
microstrip antennas in the same module
can be used to produce nearly omni
directional radiation pattern required for
LAN applications [4, 12, and 13].
Compact circular microstrip patch
antenna can be designed by embedding
suitable slots on the radiating patch and by
The effects of round bottom flask
neck slot and base are studied separately
by varying the parameters like length,
width and radius. The effect of the
thickness height also verified. All the
dimensions of the optimized CMPA are
tabulated in table 1.
III. SIMULATED RESULTS
The round bottom flask base radius
using the defected ground plane as DGS
is optimized to 2.5mm by varying the
radius (r) from 1mm to 3mm, as it
increases beyond 2.5mm then it reduces
the gain and when it reduced less than
2.5mm
then
it
shifts
the
resonant
frequency to higher frequency as shown
S11 in fig 3.
Fig 2 Top view of ground plane
3
Case (iii) the round bottom flask shape is
etched on ground plane with optimized
dimensions of neck slot and the round
bottom flask base. This defected ground
plane
helps us to relocate the resonant
frequency from 6.3GHz to 5.5GHz with
improvement in
bandwidth
to
cover
HIPERLAN/1 and HIPERLAN/2.
Fig 3 Simulated return for different radius of round
There is a good input impedance
match is observed over the operating
bottom flask base
frequency of CMPA which is compared
with all four cases as shown in fig.6.
Fig 4 Return Loss comparison for different slot width
(w)
Similarly we optimized the neck slot width of
Fig 6 Impedance Match
the round bottom flask by varying w for
different values and it is optimized to 0.5mm
and s11 comparison are as shown in fig 4.
The
simulated
return
loss
characteristics of a CMPA are examined
with three different cases and S11 are
compared as shown in Fig. 5
Case (i) The CMPA with radius a=5.5mm
and substrate thickness of 1.6mm is
considered without DGS, the resonating
frequency is at 6.95GHz.
Case (ii) The substrate thickness is
doubled that is 3.2mm so the resonating
frequency shifted to 6.3GHz.
Fig 7 the VSWR
The important property of any
antenna is VSWR in our CMPA also we
achieved VSWR < 2 over the operating
frequency is observed.
4
microstrip
antenna
(WCMPA).
The
WCMPA with DGS is fabricated and we
are awaiting the measured results. At the
time of conference we will produce the
measured results. All the parameters and
dimensions are tabulated in table.1.
Fig.8. Radiation pattern of CMPA
The radiation pattern of CMPA
showing the E and H plane co pole and
cross pole is shown in fig 8 from the plot it
is come to know that the cross pole is
suppressed when the circular slot etched
on the ground plane.
Table 1 Dimensions of CMPA
Dimensions of CMPA
Patch Radius (a)
Ground Plane Radius
(gpr)
Radius of circular slot
Length of slot
Width of the slot
Height of the substrate
S11
BW
%BW
Gain
Size Reduction
5.5mm
11.0mm
2.5mm
10mm
0.5mm
3.2mm
-30dBi
760MHz
13.86%
3.5dBi
40.37%
Fig.9. Photos of
measurement setup
the
fabricated
patch
and
ACKNOWLEDGMENT
The authors are thankful to Prof.
Debatosh Guha, Senior Member, IEEE,
IRPE,
University
of
Calcutta
and
University of Mysore for the facility and
support.
REFERENCES
IV. CONCLUSION
In this design we used effectively
the defective ground plane to improve the
bandwidth and s11, we also achieved the
size reduction of 40.37% so we can call
this one as compact wideband circular
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5
[3] F. Yang, X.-X. Zhang, X. Ye, and Y.
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Biographical notes:
Halappa R Gajera
did
his
BE
in
Electronics
and
Communications from
Karnataka University
Dharwad
(KUD),
Dharwad, Karnataka,
India and M.Tech in
Digital Electronics and Communications
from
Visveswaraiah
Technological
University (VTU), Belgaum, Karnataka,
India, He is presently working as an
Assistant Professor in the Department of
Electronics, P.G. Centre, Hemagangotri,
Hassan University of Mysore, Currently he
is pursuing his PhD in Institute of Radio
Science and Electronics, University of
Calcutta, Kolkatta, India, His areas of
interest are microstrip patch antennas,
printed antennas, Dielectric Resonator
Antennas with defected ground structures
(DGS) and defected microstrip surfaces
(DMS).
Anoop C. N. did his
B.Sc. in Electronics
from Tumkur University
(TU),
Tumkur,
Karnataka, India and
M.Sc. in Electronics
from
University
of
Mysore (UOM), Mysore, Karnataka, India,
Currently, His areas of interest are
microstrip patch antennas, printed
antennas, Dielectric Resonator Antennas
with defected ground structures (DGS) and
defected microstrip surfaces (DMS),
Metameterials.