Antenna Shape Prediction by Feedforward Neural Network
COPLANAR WAVEGUIDE-FED MONOPOLELIKE SLOT ANTENNA FOR ULTRA
WIDEBAND APPLICATIONSBy Manoj Kumar Shrivastava
Under the guidance ofDr. Amit Kumar Singh
Department of Electronics EngineeringIT BHU, Varanasi
Institute of Technology Banaras Hindu University1Seminar on
Dissertation ContentsIntroductionUltra Wideband TechnologyTypes of
Feeding TechniquesUltra wideband monopole antennaApplications of
UWB AntennaDesign of The Proposed AntennaSimulated and Measured
ResultsParametric studySimulated and Measured
ResultsConclusionReferencesInstitute of Technology Banaras Hindu
University22In the ancient age, spark-gap technology was in the
main root of ultra wideband antenna. Arguably, the first experiment
on UWB was conducted by Hertz1 in 1893
After Hertz, Oliver lodge2 gave prominent contribution in the
field of UWB antenna. In 1898
After four decades, in 1939, Carter3, who improved upon Lodges
original design by incorporating a tapered feed
Institute of Technology Banaras Hindu University3Introductionwho
was among the first to take the key step of incorporating a
broadband transition between a feed line and radiating
elements.
Deschamps4 first proposed the concept of the Microstrip antenna
(MSA) in 1953. However, practical antennas were developed by Munson
and Howell in the 1970s.
Finally5, it was in November 2002 when the interest for UWB
systems was greatly magnified by the decision of the United States
frequency regulating body, the Federal Communications Commission
(FCC)Institute of Technology Banaras Hindu University4After, 2002
UWB antenna got new direction and wide amplitude of uses.
Innovative research and design are taking place day by
day.Institute of Technology Banaras Hindu University5Ultra Wideband
Technology5Federal Communications commissions(FCC)Bandwidth ranging
from 3.1GHz to 10.6GHz Low Emission power (-41.3dBm/MHz)Radiation
pattern should be omni-directional.
Institute of Technology Banaras Hindu University6Types of
Feeding Technique4Coaxial feedMicrostrip line feedAperture
couplingProximity-coupled feedCoplanar waveguide feed
Institute of Technology Banaras Hindu University7Coplanar
waveguide feed6
Institute of Technology Banaras Hindu University8
Advantages of CPW fed are low radiation loss, less dispersion,
easy integrated circuits wider bandwidth, better impedance
matching, and easy integration with active devices or monolithic
microwave integrated circuits(MMIC) and simple configuration with
single metallic layer, and no via holes required. Institute of
Technology Banaras Hindu University9Ultra wideband monopole
antenna
There are three typical printed UWB antenna designs which has
been widely suited and used in UWB systems as shown in figure
Institute of Technology Banaras Hindu University10Figure: Three
typical printed UWB antennas: (a)A microstrip-fed monopole antenna;
(b) a CPW fed wide slot antenna; (c) a CPW fed monopole-like slot
antenna.
The antenna7 used in portable devices do not have a large ground
plane but a small floating system ground plane which is used as a
zero potential reference for systems. The system ground plane
actually act as the other radiating element of the antenna,
therefore the overall size should include both the antenna and the
system ground plane.
Institute of Technology Banaras Hindu University11 Unbalanced
dipoles
Figure printed UWB monopole antennas acting as asymmetrical
unbalanced dipoles
Institute of Technology Banaras Hindu University12
12Applications of UWB Antenna
(1) Ground penetration radar (GPR)(2) Sensing and Imaging
[biomedical and military applictions](3) Testing the systems
Institute of Technology Banaras Hindu University13Design of The
Proposed Antenna
Institute of Technology Banaras Hindu University14
Figure: Structure of CPW-fed monopole-like slot antenna for UWB
applications
Table : Optimized parameter of designed antenna
Parameters
bcdefgqrstDimensions(mm)9.32.611.510.58.5615.50.91Institute of
Technology Banaras Hindu University15The geometry of CPW-fed
monopole-like slot antenna for UWB applications is shown in figure.
The parameter of antenna is given in the table below.
The dielectric material of the antenna is FR4 ( r=4.4) and
dielectric loss tangent is 0.02. The thickness of the dielectric
material is 1.6mm and the dimension of patch is 25x25mm.
Institute of Technology Banaras Hindu University16
Figure : prototype of proposed antenna (a) Top view (b) Back
view
(a)(b)Simulated and Measured ResultsInstitute of Technology
Banaras Hindu University17Figure Simulated Return loss of the
proposed antennaMeasured Return lossInstitute of Technology Banaras
Hindu University18Figure Measured Return loss of the proposed
antenna
Comparision between measured and simulated resultReturn
LossLower cut off frequency[GHz]Upper cutoff frequency[GHz]Band
width[GHz]%
BandwidthMeasured4.9610.395.4370.75simulated3.114.5511.45129.74Institute
of Technology Banaras Hindu University19Figure Simulated H-plane
radiation pattern at different frequenciesInstitute of Technology
Banaras Hindu University20Figure Simulated H-plane radiation patter
at different frequencies
Institute of Technology Banaras Hindu University21Gain of the
antennaInstitute of Technology Banaras Hindu University22Figure
Simulated gain of the designed antenna
11.6 dB gain can be achieved at frequency at
3.1GHz , which is maximum value in the pass band wher as and0.5
dB is minimum value in pas band at 12.7GHz Measured imaginary part
of input impedance
Institute of Technology Banaras Hindu University23Measured real
part of input impedance
Institute of Technology Banaras Hindu University24Simulated
imaginary and real part of the input impedanceInstitute of
Technology Banaras Hindu University25Figure Simulated imaginary and
real part of the input impedance
Parametric study
varying the gap between CPW feeding stub and ground planes
Institute of Technology Banaras Hindu University26Figure Return
loss for varying the gap between CPW feeding stub and ground
planes
varying the patch radius of the antenna
Institute of Technology Banaras Hindu University27
Figure Return losses for varying the patch radius of the
antennaVarying the gap between lower ground plane and circular
patch.
Institute of Technology Banaras Hindu University28
Figure Return losses for varying the gap between lower ground
plane and circular patch. Varying pint p
Institute of Technology Banaras Hindu University29
Figure Return loss for varying the ground plane along the
vertical axis CONCLUSION AND FUTURE WORKA comprehensive study of
UWB antennas including design, simulation, testing and
characterization is presented.
From UWB antenna design it is found that the measured impedance
bandwidth is 70.75% where as simulated impedance bandwidth is
129.74%Institute of Technology Banaras Hindu University30Future
scopeThis proposed antenna can be modified to be usefull in band
notched UWB antennaThis can be used as directional antenna with
some physical modification.Institute of Technology Banaras Hindu
University31References [1]
http://www.intechopen.com/books/ultra-wideband/uwb-antennas-design-and-modeling[2]
O. Lodge, Electric Telegraphy, U.S. Patent 609154, August 1898[3]
P.S. Carter, Short Wave Antenna, U.S. Patent2175252, October
1939[4] Girish Kumar and K. P. Ray, Broadband Microstrip Antennas
(Artech House Boston London 2003 edition)[5]International Journal
of Antennas and PropagationUltra-Wideband AntennasGuest Editors:
James Beck er, D ejan Filipovic,Hans Schantz, and S eong-Youp
Suh.2002[6]Leena Varshney, Vibha Rani Gupta, Harish kumar,
Priyadarshi Suraj, CPW-Fed Broadband Microstrip Patch Antenna
Published in International Journal of Advanced Engineering &
Application, Jan 2011 Issue
[7] DEBATOSH GUHA AND YAHIA M.M.ANTAR; Microstrip and Printed
Antennas New, Trends, Techniques and pplications.(A John Wiley and
Sons, Ltd, publication, 2011)Institute of Technology Banaras Hindu
University32
THANK YOUInstitute of Technology Banaras Hindu
University33Institute of Technology Banaras Hindu University34