Design of a UWB Planar Monopole Antenna for Breast Cancer … · 2018-06-16 · Design of a UWB Planar Monopole Antenna for Breast Cancer Tumour Detection Using HFSS 1N. Krishna Jyothi

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.

[email protected]

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

International Journal of Pure and Applied Mathematics Special Issue

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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

[1] Ruzdiana S.A., An UWB Antenna Array for Breast Cancer Detection (2011).

[2] Hagness S.C., Bond E.J., Li X., Van Veen B.D., Microwave imaging via space- time beam forming for early detection of breast cancer, IEEE Trans. Antenna propag. 51(8) (2003), 1690-1705.

[3] Wang Y., Bakar A.A., Bialkowski M.E., Compact Tapered Slot Antennas for UWB Microwave Imaging Applications, IEEE Microwave Radar and Wireless Communications (2010), 1-4.

[4] Ghosh D., Taylor M.C., Sarkar T.K., Wicks M.C., Mokole E.L., Transmission and reception by ultra wideband antennas, IEEE antennas and propagation magazine 48(5) (2006), 67-99.

[5] National Breast Cancer Coalition (NBBC), 2004.

[6] Yu J., Yuan M., Liu Q.H., A wideband half oval patch antenna for breast imaging, Progress in Electromagnetics Research 98 (2009), 1-13.

[7] Abbosh A., Directive antenna for ultra wideband medical imaging systems, Antennas and Propagation (2008).

[8] Agrawall N.P., Kumar G., Ray K.P., Wide-band planar monopole antennas, IEEE Transaction on Antennas and Propagation 46(2)


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(1998), 294–295.

[9] Stuchly M.A., Okoniewski M., A study of the handset antenna and human body interaction, IEEE Trans. microwave Theory Techl, (1996), 1855-l864.

[10] James S.E., Jusoh M.A., Mazwir M.H., Mahmud S.N.S., Finding The Best Feeding Point Location of Patch Antenna using HFSS, ARPN Journal of Engineering and Applied Sciences 10 (23) (2015).

[11] https://en.wikipedia.org/wiki/FR-4, 2017.


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Design of a UWB Planar Monopole Antenna for Breast Cancer … · 2018-06-16 · Design of a UWB Planar Monopole Antenna for Breast Cancer Tumour Detection Using HFSS 1N. Krishna Jyothi