Design and Analysis of Band-Notched UWB Printed Monopole Antenna using Multiple Slots
Design of a UWB Planar Monopole Antenna for Breast Cancer … · 2018-06-16 · Design of a UWB...
Transcript of Design of a UWB Planar Monopole Antenna for Breast Cancer … · 2018-06-16 · Design of a UWB...
Design of a UWB Planar Monopole Antenna for
Breast Cancer Tumour Detection Using HFSS 1N. Krishna Jyothi and
2N. Harini
1Department of Electronics and Communication Engineering,
G. Narayanamma Institute of Technology and Science,
Hyderabad, India.
[email protected] 2Department of Electronics and Communication Engineering,
G. Narayanamma Institute of Technology and Science,
Hyderabad, India.
Abstract This paper covers the design of an ultra-wide band planar monopole
antenna working in the frequency range from 5-10 GHz.The antenna has
very compact size (area of 9 mm * 10.5 mm) and is immersed to liquid of
high dielectric constant for breast tissue to be improved and increase the
dynamic range of the system. The time domain performance of the antenna
is to show the negligible distortion so that can make it perform better for
medical imaging systems. Due to the better performance of the antenna the
effect of the multilayer breast tissue is also investigated by calculating the
fidelity factor across all the tissue layers. Now for better performance and
to meet the requirements a Planar Monopole Antenna (PMA) is designed
and optimized regarding to different parameters. A crossslot has been
introduced to the design to find the better result. The simulated results
show the reflection coefficients of designed antenna are less than 10dB over
the entire frequency band of interest.
Key Words:Planar monopole antenna, ultra wide band, HFSS,
bandwidth, return loss, VSWR.
International Journal of Pure and Applied MathematicsVolume 119 No. 15 2018, 37-47ISSN: 1314-3395 (on-line version)url: http://www.acadpubl.eu/hub/Special Issue http://www.acadpubl.eu/hub/
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1. Introduction
The main objective of the paper is to design, fabricate and test the planar
monopole antenna. It is mainly designed to resonate at a frequency which is
acceptable for UWB applications. For the design of Planar monopole antenna
operating at specific resonating frequency the dimensions of substrate, patch
and height should be accurate. Therefore, it is necessary to use simulation
programs to test the antenna performance before fabrication. For simulation
procedure of patch antennas HFSS (High Frequency Structural Simulator) is
used in general.
Ultra-Wide Band (UWB) is a communication method used in wireless
networking to achieve high bandwidth connections with low power utilization.
Ultra-wide band wireless radios send short signal pulses over a broad spectrum.
For example, a UWB signal centered at 5 GHz typically extends across 4 GHz
and 6 GHz. The wide signal allows UWB to commonly support high wireless
data rates of 480 Mbps up to 1.6 Gbps at distances up to a few meters.
2. Basic Steps Involved in HFSS
Design Procedure
The name HFSS stands for High Frequency Structural Simulator. HFSS is a
high-performance full-wave electromagnetic (EM) field simulator for arbitrary
3D volumetric passive device modelling that takes advantage of the familiar
Microsoft Windows graphical user interface. It integrates simulation,
visualization, solid modelling, and automation in an easy-to-learn environment
where solutions to 3D EM problems are quickly and accurately obtained. Ansoft
HFSS employs the Finite Element Method (FEM), adaptive meshing, and
brilliant graphics to give unparalleled performance and insight to all of 3D EM
problems.
The following is a flow chart which depicts about the basics steps involved in
HFSS design procedure.
Fig. 1: Basic Steps Involved in HFSS Design Procedure
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3. Antenna Feeding Techniques
A feedline is used to excite to radiate by direct or indirect contact. There are
many different methods of feeding and four most popular methods are micro
strip line feed, coaxial probe, aperture coupling and proximity coupling. In this
paper line feeding technique is used to design the planar monopole antenna. In
this type of feed technique, a conducting strip is connected directly to the edge
of the Planar Monopole patch. The conducting strip is smaller in width as
compared to the patch and this kind of feed arrangement has the advantage that
the feed can be etched on the same substrate to provide a planar structure as
shown in Figure 2.
Fig. 2: Line Feeding
4. Parameters of a Planar Monopole
Antenna
The three essential parameters for the design of a Planar Monopole antenna are:
Frequency of operation (fr):. The resonant frequency selected for design is
5.75 GHz.
Dielectric constant of the substrate(εr): The dielectric material selected for the
design is FR4-epoxy which has a dielectric constant of 4.4. A substrate with a
high dielectric constant reduces the dimensions of the antenna.
Height of dielectric substrate (h): For the antenna it is essential that the antenna
is not bulky. Hence, the height of the dielectric substrate is selected as 0.8mm.
Step 1: Calculation of the Width (W): The width of the Planar Monopole patch
antenna is given by following equation:
….….. (4.1)
Substituting εr=4.4, vo=3.00×108 m/sec, fo= 5.75GHz gives: W=9mm
Step 2: Calculation of Effective Dielectric Constant (εreff): The following
equation gives the effective dielectric constant as:
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..…….. (4.2)
Substituting εr=4.4, W=9mm, h=0.8 mm gives εreff =3.7
Step 3: Calculation of Effective Length ( eff L ): The effective length is given
as:
…........ (4.3)
Substituting fo=5.75GHz, vo=3.00×108 m/sec, εreff =3.7 gives Leff
Step 4: Calculation of the Length Extension (ΔL): Equation below gives the
length extension as:
………. (4.4)
Substituting the values, the length extension (ΔL) is obtained
Step 5: Calculation of Actual Length of Patch (L): The actual length of the
antenna can be calculated as:
….…… (4.5)
Substituting Leff and ΔL the actual length come out to be: L=10.5mm
The shape of the patch is its main parameter and it naturally affects most of the
antenna characteristics. The patch width has a minor effect on the resonant
frequency, but it has a major effect on the bandwidth. Therefore height of the
substrate and the width of the patch play an important role for the maximizing
of the radiation efficiency and the bandwidth of the antenna.
The various parameters of the patch antenna which includes shape of the patch,
dielectric used, length and width of the patch thickness of patch and length and
width of the slot as shown in table below.
Table 1: Parameters of a Planar Monopole Antenna Parameter Dimensions(mm)
Patch height (B) 4.77
Patch width (A) 8.52
Patch thickness (Px) 0.2
Microstrip Feed line height (Fl) 5.25
Microstrip Feed line width (Fw) 0.3
Microstrip Feed line thickness (Ft) 0.2
Substrate height (Sl) 10.5
Substrate width (Sw) 9
Substrate thickness (Sx) 0.8
Ground height (Gl) 4.77
Ground width (Gw) 8.52
Ground thickness (Gx) 0.00001
Gap between patch bottom edge and Ground plane(P) 0.48
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5. Design of a Planar Monopole Antenna
The essential parameters for the design are
Resonant frequency (f0) = 5.75GHz
Dielectric constant (εr) = 4.4
Substrate thickness (h) = 0.8mm
Fig. 3: View of A Planar Monopole Antenna
(i) The Top View of the Antenna (ii) The Side View of the Antenna (iii) The
Bottom View of the Antenna with Partial Ground
By following the above parameters as mentioned in the table, a planar
monopole antenna has been designed and simulated in HFSS at resonant
frequency of 5.75GHz.The material used for substrate is FR4 epoxy.FR4 epoxy
glass substrates are the material of choice for most PCB applications. The
material is very low cost and has excellent mechanical properties, making it
ideal for a wide range of electronic component applications.
6. Simulation Results
The simulated results of radiation characteristics plots for above design are
given below. The Return loss versus frequency plot has the peak value of -11.5
dB at a resonating frequency of 5.75 GHz is shown in figure 4. A The VSWR of
the designed antenna is observed to be 1.7 dB at the resonating frequency of
5.75GHzis presented in the figure 5. It has a Gain of 9 dB and directivity of 2
dB which are also shown in the figures 6 and 7.
Fig. 4: Return Loss versus Frequency Plot
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Fig. 5: VSWR versus Frequency Plot
Fig. 6: Gain versus Frequency Plot
Fig. 7: Directivity versus Frequency Plot
7. Fabrication and Testing Process
The fabricated design of the planar monopole antenna is as shown in thefigure
below:
Fig. 8: Front View of the Antenna
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Fig. 9: Back View of the Antenna
Design Flow Chart for Fabrication
In this topic whole fabrication procedure of the antenna using proximity feeding
technique is covered. The flow chart of the antenna fabrication is given below:
The simulated and tested results are 90% matched, the 10% losses are due to
lose soldering connections, due to presence of air or due to lose SMA connector
connections. After these small variations in the results due to some reasons the
results are still acceptable.
Testing Using the Vector Network Analyzer
R&S®ZVL-13 comes with a calibration device by which the cables attached to
it can be calibrated and provide accurate results. Before starting the experiment,
the centre frequency and the frequency range is to be entered. Then the
calibration is performed for the specified range with respect to open circuit,
short circuit and matched load termination. After calibration, the DUT is
connected and network parameters can be observed. The tested results of
radiation characteristic plots are given below. The Return loss versus frequency
plot has the peak value of -18dB at a resonating frequency of 5.75 GHz is
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shown in figure10. A The VSWR of the designed antenna is observed to be
1.55at the resonating frequency of 5.75GHz is presented in the figure11.
Fig. 10: Return Loss
Fig. 11: VSWR
8. Applications
Microwave Imaging System for Breast Cancer Detection
In microwave breast cancer tumor detection system a very narrow pulse is being
transmitted from one antenna to penetrate the breast tissue. The scattered signal
cause of different layer of breast tissue is collected by other remaining antennas
of the array surrounding the breast tissue. Then the signal processing algorithm
can investigate the existence of any cancerous tissue in breast. The process is
being repeated until all the antennas of the array have been used simultaneously
as transmitter and scattered fields are recorded. The second step involves the
reconstruction of dielectric properties profiles of the object under test with the
use of measuring scattered fields.
The figure 12 shows the microwave imagine system for breast cancer detection.
Fig. 12: Block diagram of Microwave Imaging Systems for Breast Cancer Detection
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Short-range wireless communication is different from traditional carrier wave
system. UWB waveforms are short time duration and have some rather unique
properties. Recent years, rapid developments have been experimented on the
technologies using UWB signals. UWB technology offer major enhancements
in three wireless application areas: Medical applications, Communication
systems, Radar and GPS and Ranging.
9. Conclusion
In this paperUWB Planar Monopole antenna is proposed and a prototype is
fabricated. A slot is introduced into the rectangular patch and partial ground
technique is used to expand its bandwidth and to reduce the size of antenna. The
simulation of Planar Monopole patch antenna is carried out using HFSS. The
design achieves return loss of -11.5dB and corresponding VSWR is 1.7 with a
Gain of 9 dB and Directivity of 2. The fabricated antenna has been tested and
the test results of the performance of the antenna have been almost close to the
simulated values. The fabricated design achieves good returnloss of -18dB and
the corresponding VSWR is 1.55. Simulated results and the test results of the
antenna show that the proposed antenna is suitable for UWB and Medical
applications. The research has been motivated by their potential use in future
applications in Medical industry for cancer detection at early stages.
References
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[11] https://en.wikipedia.org/wiki/FR-4, 2017.
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