Minor Research Project On - SDM College, Ujire MRP REPORT.pdf · I hereby declare that the minor research project entitled ... The aim of the project is to design and fabricate a

1

SRI DHARMASTHALA MANJUNATHESHWARA COLLEGE

(AUTONOMOUS)UJIRE-574140

(Re-Accredited at ‘A’ Grade with CGPA 3.61 by NAAC)

Minor Research Project

On

DESIGN OF MICROSTRIP ANTENNA FOR

INTENSIVE INVESTIGATION OF HIGHER BANDWIDTH

Submitted to

University Grants Commission

South West Regional Office

Bangalore

By

S N KAKATHKAR

Principal Investigator

Department of Physics

SDM College Ujire-574240

May -2016

2

SRI DHARMASTHALA MANJUNATHESHWARA COLLEGE

(AUTONOMOUS)UJIRE-574140

(Re-Accredited at ‘A’ Grade with CGPA 3.61 by NAAC)

Minor Research Project

On

DESIGN OF MICROSTRIP ANTENNA FOR

INTENSIVE INVESTIGATION OF HIGHER BANDWIDTH

Submitted to

University Grants Commission

South West Regional Office

Bangalore

By

S N KAKATHKAR

Principal Investigator

Department of Physics

SDM College Ujire-574240

May -2016

3

CERTIFICATE

I hereby declare that the minor research project entitled “DESIGN OF

MICROSTRIP ANTENNA FOR INTENSIVE INVESTIGATION OF

HIGHER BANDWIDTH” has been carried out by me in the department of

Physics of our college granted by University Grants commission, New Delhi.

I further declare that the work contained in this report has not formed the

basis for the award of any degree of any university

Ujire S N Kakathkar

1-5-2016

4

ACKNOWLEDGEMENT

I am grateful to the management of our Institution SDME Society ,

particularly President of the Institution Dr D Veerendra Heggade,Vice

President ,Secretaries and Prof Mohannarayan K. S. Principal of the

Institution for all encouragement and timely support.

The University Grants Commission provided the crucial support that made

the project a reality. I acknowledge my indebtedness to the joint secretary and

Regional Head of UGC, Bangalore

I am grateful to Prof T N Keshav HOD of Physics and Dr Nandakumar Shetti

associate professor PG Physics SDMC Ujire for their guidance and support

I feel great pleasure in expressing my sincere thanks to all those who helped

directly and indirectly in completing this work.

S N Kakathkar

5

CONTENTS

Sl no Title Page no

1. Introduction 6

2. Objectives 8

3. Relevance of the study 9

4. Research design and methodology 11

5. Chapter - 1-antenna of circular shape 13

6. Chapter -2-Bandwidth enhancement-parasitic patches 16

7. Chapter 3-Bandwidth enhancement –additional lobes 21

8. Chapter- 4- Bandwidth enhancement –additional lobes 26

9. Observation s and Tabulations 29

10. Summary of findings 37

11. References 39

6

Introduction:

An antenna is a radiating element which is used to transmit and receive

electromagnetic waves.

Wireless communications has been developed widely and rapidly in the modern

world especially during the last two decades. The future development of the

personal communication devices will aim to provide image, speech and data

communications at any time, and anywhere around the world. This indicates that

the future communication terminal antennas must meet the requirements of multi-

band or wideband operations to sufficiently cover the possible operating bands.

However, the difficulty of antenna design increases when the number of operating

frequency bands increases within a single antenna.

The aim is to study and design various micro strip patch antennas of different

shapes for wireless communication systems and the investigation of higher

bandwidth

Microstrip Antenna

A microstrip antenna consists of conducting patch on a ground plane separated by

dielectric substrate. This concept was undeveloped until the revolution in

electronic circuit miniaturization and large-scale integration in 1970. After that

many authors have described the radiation from the ground plane by a dielectric

substrate for different configurations.

The first practical antenna was developed by Howe and Munson The early work

of Munson on micro strip antennas for use as a low profile flush mounted antennas

on rockets and missiles showed that this was a practical concept for use in many

antenna system problems. Various mathematical models were developed for this

antenna and its applications were extended to many other fields. A microstrip

7

antenna is characterized by its Length, Width, Input impedance, and Gain and

radiation patterns.

Various parameters of the microstrip antenna and its design considerations are to

be discussed.. The length of the antenna is nearly half wavelength in the dielectric;

it is a very critical parameter, which governs the resonant frequency of the antenna.

There are no hard and fast rules to find the width of the patch.

History

The rapid development of microstrip antenna technology began in the late 1970‟s.

The first aperture coupled microstrip antenna was fabricated and tested by a

graduate student, Allen Buck, on August 1, 1984, in the University of

Massachusetts Antenna Lab. This antenna used 0.062” Duroid substrates with a

circular coupling aperture, and operated at 2 GHz. As is the case with most original

antenna developments, the prototype element was designed without any rigorous

analysis or CAD - only an intuitive view of how the fields might possibly couple

through a small aperture. They were pleasantly surprised to find that this first

prototype worked almost perfectly – it was impedance matched, and the radiation

patterns were good. Most importantly, the required coupling aperture was small

enough so that the back radiation from the coupling aperture was much smaller

than the forward radiation level.

The geometry of the basic aperture coupled patch antenna is described. The

radiating microstrip patch element is etched on the top of the antenna substrate,

and the microstrip feed line is etched on the bottom of the feed substrate. The

thickness and dielectric constants of these two substrates may thus be chosen

independently to optimize the distinct electrical functions of radiation and

circuitry. Although the original prototype antenna used a circular coupling

8

aperture, it was quickly realized that the use of a rectangular slot would improve

the coupling, for a given aperture area, due to its increased magnetic polarizability.

Most aperture coupled microstrip antennas now use rectangular slots, or variations

thereof.

(iii.) Objectives:

. The aim of the project is to design and fabricate a Microstrip Antenna for the

intensive study of higher band width for various patterns.

(iv) Hypothesis:

Bandwidth is a fundamental antenna parameter. Bandwidth describes the range

of frequencies over which the antenna can properly radiate or receive energy., the

desired bandwidth is one of the determining parameters used to decide upon an

antenna. For instance, many antenna types have very narrow bandwidths and

cannot be used for wideband operation.

Bandwidth is typically quoted in terms of VSWR. For instance, an antenna may be

described as operating at 100-400 MHz with a VSWR<1.5. This statement implies

that the reflection coefficient is less than 0.2 across the quoted frequency range.

Hence, of the power delivered to the antenna, only 4% of the power is reflected

back to the transmitter. Alternatively, the return lossS11=20*log10(0.2)=-13.98

dB.

This does not imply that 96% of the power delivered to the antenna is transmitted

in the form of EM radiation; losses must still be taken into account.

9

Ways of optimizing the substrate properties for increased bandwidth

1. Printing the antenna on a thicker substrate

2. Decreasing dielectric constant of the substrate

3. Stacking two patches on the top of each other separated by a dielectric

substrate.

4. Design of antennas of different patterns other than geometrical patterns such as

flowers.

(v) Relevance of the Study:

Microstrip patch antennas are increasing in popularity for use in wireless

applications due to their low-profile structure. Therefore they are extremely

compatible for embedded antennas in handheld wireless devices such as cellular

phones, pagers etc. The telemetry and communication antennas on missiles need to

be thin and conformal and are often in the form of microstrip patch antennas.

Another area where they have been used successfully is in satellite communication.

10

Advantages

• Light weight and low volume.

• Low profile planar configuration which can be easily made conformal to host

surface.

• Low fabrication cost, hence can be manufactured in large quantities.

• Supports both, linear as well as circular polarization.

• Can be easily integrated with microwave integrated circuits (MICs).

• Capable of dual and triple frequency operations. •

Mechanically robust when mounted on rigid surfaces.

disadvantages

• Narrow bandwidth.

• Low efficiency.

• Low Gain.

• Extraneous radiation from feeds and junctions.

• Poor end fire radiator except tapered slot antennas.

• Low power handling capacity.

• Surface wave excitation.

Microstrip patch antennas have a very high antenna quality factor (Q). It represents

the losses associated with the antenna where a large Q leads to narrow bandwidth

and low efficiency. Q can be reduced by increasing the thickness of the dielectric

substrate. But as the thickness increases, an increasing fraction of the total power

11

delivered by the source goes into a surface wave. This surface wave contribution

can be counted as an unwanted power loss since it is ultimately scattered at the

dielectric bends and causes degradation of the antenna characteristics. Other

problems such as lower gain and lower power handling capacity can be overcome

by using an array configuration for the elements

(vi.) Research Design and Methodology:

In its most fundamental form, a microstrip patch antenna (MPA) consists of

a radiating patch on one side of a dielectric substrate which has a ground plane on

the other side as shown .The patch is generally made of conducting material such

as copper or gold and can take any possible shape. The radiating patch and the feed

lines are usually photo etched on the dielectric substrate.

In order to simplify analysis and performance prediction, the patch is generally

square, rectangular, circular, triangular, and elliptical or some other common shape

.

Microstrip patch antennas radiate primarily because of the fringing fields between

the patch edge and the ground plane. For good antenna performance, a thick

dielectric substrate having a low dielectric constant is desirable since this provides

better efficiency, larger bandwidth and better radiation .However; such a

12

configuration leads to a larger antenna size. In order to design a compact

microstrip patch antenna, substrates with higher dielectric constants must be used

which are less efficient and result in narrower bandwidth. Hence a trade-off must

be realized between the antenna dimensions and antenna performance

13

Chapter 1

Antenna of circular shape and the same between two rectangles

1. For the initial study a circular patches is designed.

2. Using IE3D software feed point is located for a best return loss

3. for the designed frequency of 10 GHz at the feed point of (2.5,-0.5).a return

loss of -33dB is obtained with band width 1.8 GHz

4. When two rectangles for frequencies 9 GHz and 11 GHz re placed on either

side of the circular patch at a gap of 2.5 mm, at the same feed point a return

loss of -46 is obtained with increased bandwidth by 16 percent.

Circular patch return loss curve

Parasitic patch return loss curve

14

DESIGN CALCULATIONS

Middle Circle:

Assumed frequency = 10 GHz

Radius, R = 1.8412× C

2×Π×fo×√ξ

= 1.8412×3×10^8

2×3.14×10×10^9×√4.2

= 4.5mm

Right Rectangle:

Assumed frequency =11GHz

Width =c/(2fo√(є+1)/2)

=3x108/(2)(11x109(√(4.2+1)/2)

= (3x108)/3.5464X1010

=8.45mm

Length = c/(2fo√є)

=3x108/((2)(11x109(√4.2))

=3x108)/4.5086x1010

=6.653mm

Left rectangle

assumed frequency = 9 GHz

Width =c/(2fo√(є+1)/2)

=3x108/(2)(9x109(√(4.2+1)/2)

= (3x108)/3.5464X1010

15

=10.33mm

Length = c/(2fo√є)

=3x108/((2)(9x109(√4.2))

=3x108)/4.5086x1010

=8.13 mm

Conclusion

The analysis reveals that Return loss increased to -46 dB for 2.5mm gap. For

circular patch it is only -33dB. And the bandwidth increased by 16% The gap-

coupling is the potential method to enhance the bandwidth of the conventional

microstrip antennas. For multi-band applications also, the gap-coupling is suitable

method. Various structures using different types and sizes of the patches, number

of patches, gap-coupled microstrip antennas can be designed for various

applications. Gap-coupling along with some other bandwidth enhancement

techniques can be used together to produce ultra large bandwidth, and the antennas

can be designed for various wideband applications.

16

CHAPTER 2

BANDWIDTH ENHANCEMENT IN PARASITIC MICROSTRIP ANTENNAS:

The bandwidth of the microstrip antennas can be improved by using the gap-

coupled structure. In this structure, two parasitic rectangular patches are placed

close to the feed patch which is circular as shown in Fig. 1, and gets excited

through the coupling between the patches. The feed patch is excited by a feeding

method and the parasitic patch is excited by gap-coupling. If the resonant

frequencies of these three patches are close to each other, then broad bandwidth is

obtained as shown in Fig. 2. The overall input return loss will be the superposition

of the responses of the two resonators resulting in a wide bandwidth . By adjusting

the feed location and gap between the patches, the bandwidth can be enhanced.

Figure 1

figure 2

17

RESEARCH REVIEW:

The basic configuration of two dipoles gap-coupled to a radiating patch was

reported in 1979 . When two patches were gap-coupled to the main patch along the

radiating edges, a maximum bandwidth up to 5.1 times that of a single rectangular

patch antenna was obtained This type of parasitic coupling along the non-radiating

edges in yielded 4 times the bandwidth.

A parametric study has been carried out using IE3D software. The configuration

with these patches yielded a bandwidth of 2.1 GHz with MAXIMUM RETURN

LOSS OF -46dB for a gap of 2.5 mm for resonance frequency 11.15GHz. The

assumed center frequency for the circular patch is 10 GHz, and other rectangular

patches 9 and 11 GHz, respectively. Only for the circular patch bandwidth

obtained is 1.8 GHz and the return loss is -33 dB. Thus 16% increase in BW is

observed. Theoretical interpretations is yet to be carried out

DESIGN CALCULATIONS:

For the central circular patch resonance frequency is 10 GHz, the radius is given by

Radius,

R = 1.8412× C/ 2×Π×fo×√ξ = 4.3mm

Right rectangle:Assumed frequency=11GHz,

Width= c/(2fo√(є+1)/2) = 6.65mm

Length = c/(2fo√є =8.45mm

Left rectangle: Assumed frequency=9GHz

width=c/(2fo√(є+1)/2) =10.33mm

Length= c/(2fo√є)= =8.13mm

Dielectric constant=4.2,Thickness of the medium=1.6mm Tangent loss=0.001

18

THEORY:

In this model the MSA can be represented by two slots of width (W) and height (h)

separated by transmission line of length (L). The width of the patch can be

calculated from the following equation.

The effective dielectric constant (εeff) is less than (εr) because the fringing field

around the periphery of the patch is not confined to the dielectric speared in the air

also.

For TM10 Mode the length of the patch must be less than (λ /2) .This difference in

the length (ΔL) which is given empirically by

Radius of the circular patch is given by R=1.8412× C/ 2×Π×fo×√ξ

. Where c=speed of light, Leff = effective length. Fr=resonance frequency, εeff =

effective dielectric constant

EXPERIMENTAL OBSERVATIONS:

Using IE3D Software simulation is carried out for feed position (2.5,-0.5) only for

the circular patch and a return loss of is -33 dB and band width is 1.8 GHz is

obtained for the resonance frequency of 10.9 GHz as shown below(fig 3). Similar

analysis is done for the parasitic patch and the results are compared. Return loss

against gap and bandwidth against gap are analyzed

19

Circular patch figure 3 return loss

Variation of return loss with gap variation of bandwidth with gap

TABULATIONS

Gap in

mm

Return

loss

IN -dB

BW

IN

GHz

Resonance

frequency

in GHz

1 36.5 2.6 10.9

1.5 35 2.4 11

2 42 2.3 11.1

2.5 46 2.1 11.15

3 41 2.1 11.15

3.5 35 1.95 11.2

4 32 1.9 11.15

4.5 28 1.5 11.2

5 27.5 1.8 11.1

5.5 26 1.7 11.1

0

10

20

30

40

50

0 2 4 6

RT

GAP

0

1

2

3

0 2 4 6

BW

GAP

20

CONCLUSION:

The analysis reveals that Return loss decreases with the gap between the patches

and reaches a maximum of -46 dB for 2.5mm gap. For circular patch it is only -

33dB.Band width decreases with the gap, Resonance frequency varies with the

gap. The gap-coupling is the potential method to enhance the bandwidth of the

conventional microstrip antennas. For multi-band applications also, the gap-

coupling is suitable method. Various structures using different types and sizes of

the patches, number of patches, gap-coupled microstrip antennas can be designed

for various applications. Gap-coupling along with some other bandwidth

enhancement techniques can be used together to produce ultra large bandwidth,

and the antennas can be designed for various wideband applications.

21

CHAPTER 3

BANDWIDTH ENHANCEMENT WITH ADDITIONAL LOBES

When two rectangular lobes of length 1.5 mm and width 4.5 mm are attached with

a separation of 1.5 mm(fig 4), the shape resembles PRAANA MUDRA WITH

LEFT HAND the patch gave a return loss of -45 dB (fig 5)for a resonance

frequency of 11.2 GHz at the same feed point with band width of 2.1 GHz. Thus

16% increase in BW is observed. Theoretical interpretations is yet to be carried out

Fig 4

Fig 5

22

this MSA can be represented by a circular patch with the addition of two direct

coupled rectangular patches width (W) and length Leff The width of the patch can

be calculated from the following equation.

The effective dielectric constant (εeff) is less than (εr) because the fringing field

around the periphery of the patch is not confined to the dielectric speared in the air

also.

For TM10 Mode the length of the patch must be less than (λ /2) .This difference in

the length (ΔL) which is given empirically by

For the circular patch resonance frequency is 10 GHz (f1), the radius is given by

R = 1.8412× C/ 2×Π×fo×√ξ = 4.5 mm

Length of the additional lobes is randomly selected as 1.5 mm and separation is

1.5 mm. Width is selected as 4.5 mm. using the above mentioned formula

resonance frequency corresponding to length 1.5 mm is 48 GHz(f3) Resonance

frequency corresponding to width 4.5 mm is 14 GHz.(f2)

The empirical formula for resultant resonance frequency is

f0=f1+{(f3/f2)-2}1/2

=10X109 +{(48X109/14X109)-2}1/2

=11.195X109

=11.195GHz

23

This agrees very well with the observed frequency 11.2 GHz

Smith chart 2D radiation pattern

VSWR Curve

EXPERIMENT –PART 11

To verify the above proposed empirical formula different patches of different

frequencies are designed and in each case observed resonance frequency and

frequency obtained by empirical formula are compared. In each case length of the

lobe and separation is one third of the radius and width is equal to the radius of the

circular patch. Results are tabulated in the following tables.

24

Table 1

Patch Radius R in mm

Length In mm

Width in mm

Separation In mm

Resonance frequency of circular patchIn HzF1

1 3.9 1.3 3.9 1.3 11

2 4.3 1.43 4.3 1.43 9.98

3 4.5 1.5 4.5 1.5 9.53

4 5.1 1.7 5.1 1.7 8.41

5 6 2 6 2 7.15

Table 2

Patch

Resonance frequency as per the width of the lobIn GHz F2

Resonance frequency as per the length of the lobIn GHzF3

Observed frequency for the patch In GHz F0

Frequency as per the empirical formula In GHz F0

Error in %

1 23.85 56.30 11.25 11.6 3

2 21.63 51.18 11.4 10.57 7

3 20.67 48.8 10.9 10.13 7

4 18.23 43.05 10 9.02 9

5 15.50 36.6 7.7 7.75 .6

Following (fig 7) is the graph comparing the observed and theoretical resonance frequencies.

Fig 7

0

2

4

6

8

10

12

14

0 2 4 6

reso

nan

ce f

req

ue

ncy

in G

Hz

trial no

observed

as per formula

25

FURTHER STUDY

Similar experiment can be performed for different patches of different frequencies,

resonance frequencies obtained by IE3D simulation can be compared with the

value obtained by empirical formula and a relevant theory can be developed

RESULT AND CONCLUSION

Analysis revealed that addition of patches enhanced the bandwidth by nearly 16

percent.. Addition of patches is the potential method to enhance the bandwidth of

the conventional microstrip antennas. For multi-band applications also, this is

suitable method. Various structures using different types and sizes of the patches,

number of patches, such microstrip antennas can be designed for various




The empirical formula almost holds good for all trials within the experimental

errors. In coming days suitable theory can be developed which may agree very

well with the experimental results.

26

CHAPTER 4

BANDWIDTH ENHANCEMENT WITH ADDITIONAL LOBES

When two rectangular lobes of length 1.5 mm and width 4.5 mm are attached with

a separation of 6 mm(fig 4), the shape resembles APAANA MUDRA the patch

gave a return loss of -40 dB (fig 5)for a resonance frequency of 9.36 GHz at the

same feed point(-.89,-.5) with band width of 14.1%. Thus 69 % increase in BW is

observed. Theoretical interpretations is yet to be carried out

Fig 4

Fig 5

27

EXPERIMENT –PART 11

With the intension of enhancing the bandwidth the patch is kept between two

rectangles as shown above (fig 6)with a gap of 2mm between them.here resonance

frequency of the right rectangular patch is 11 GHz with length 8.13mm and width

10.33 mm.resonance frequency of the left rectangular patch is 9 GHz with length

6.65mm and width 8.45 mm.

When this parasitic patch is excited using IE3D software ,at the feedpoint of

(2.05,-.5) good band width is 19.24% is obtained (fig 7)with a return loss of -36

Db.Thus APAANA MUDRAA Shape between two rectangles gives a bandwidth

enhancement of 36 %. Or overall increase of 130%.

Fig 7

28

FURTHER STUDY

Similar experiment can be performed for different patches of different frequencies;

resonance frequencies obtained by IE3D simulation can be compared


Analysis revealed that addition of patches enhanced the bandwidth by nearly130


the conventional microstrip antennas. For multi-band applications also, this is

suitable method. Various structures using different types and sizes of the patches,

number of patches, such microstrip antennas can be designed for various




29

CHAPTER 5

Observations and tabulations

Antenna 1.

Radius =3.9mm.PRANA MUDRA SHAPE.

Antenna shape

Simulated return loss curve

Observations and experimental return loss curve

frequency input output RT dB

10 0.88 0.153 -15.1958

10.1 0.85 0.135 -15.9817

10.2 0.836 0.122 -16.7169

10.3 0.832 0.092 -19.1267

10.4 0.89 0.053 -24.5023

10.5 0.94 0.023 -32.228

10.6 1.011 0.038 -28.4994

30

10.7 1.043 0.072 -23.219

10.8 0.94 0.91 -0.28173

10.9 0.75 0.098 -17.6767

11 0.624 0.106 -15.3976

11.1 0.543 0.116 -13.4068

11.2 0.492 0.142 -10.7935

11.3 0.48 0.155 -9.81819

11.4 0.471 0.13 -11.1816

11.5 0.48 0.081 -15.4551

11.6 0.493 0.024 -26.2527

11.7 0.503 0.001 -54.0314

11.8 0.485 0.011 -32.887

11.9 0.4 0.032 -21.9382

12 0.253 0.038 -16.4667

12.1 0.222 0.036 -15.801

12.2 0.179 0.03 -15.5146

12.3 0.159 0.026 -15.7285

12.4 0.126 0.022 -15.159

12.5 0.133 0.011 -21.6492

12.6 0.114 0.002 -35.1175

12.7 0.094 0.009 -20.3777

12.8 0.075 0.009 -18.4164

12.9 0.048 0.006 -18.0618

13 0.032 0.004 -18.0618

Radiation pattern study

degrees current in µA

0 0

10 0.013

20 0.034

30 0.046

-60

-50

-40

-30

-20

-10

0

11.3 11.4 11.5 11.6 11.7 11.8 11.9 12 12.1 12.2

Series1

31

40 0.058

50 0.068

60 0.076

70 0.071

80 0.065

90 0.064

100 0.068

110 0.067

120 0.058

130 0.035

140 0.009

150 0.008

160 0.001

Experimental values

Antenna 2.

PRAANA MUDRA SHAPE RADIUS=4.5 mm

0

0.02

0.04

0.06

0.08

0 102030405060708090100110120130140150160170

Series1

32

Simulated return loss curve

Observations and experimental return loss curve

frequency output input Ret Loss in dB

8 0.039 0.754 -25.7261

8.1 0.045 0.739 -24.3086

8.2 0.045 0.63 -22.9226

8.3 0.047 0.53 -21.0436

8.4 0.049 0.441 -19.0849

8.5 0.055 0.389 -16.9917

8.6 0.055 0.357 -16.2461

8.7 0.048 0.343 -17.0811

8.8 0.03 0.353 -21.4131

8.9 0.016 0.364 -27.1396

9 0.01 0.386 -31.7317

9.1 0.016 0.455 -29.0778

9.2 0.046 0.522 -21.0983

9.3 0.1 0.606 -15.6495

9.4 0.143 0.698 -13.7704

9.5 0.193 0.804 -12.394

9.6 0.195 0.84 -12.6849

9.7 0.165 0.849 -14.2285

9.8 0.151 0.826 -14.7601

9.9 0.14 0.791 -15.041

10 0.141 0.762 -14.6547

10.1 0.14 0.769 -14.796

10.2 0.139 0.784 -15.026

10.3 0.129 0.862 -16.4984

10.4 0.098 0.929 -19.5358

10.5 0.06 1.016 -24.5748

10.6 0.037 1.077 -29.2803

10.7 0.043 1.065 -27.8776

33

10.8 0.06 0.94 -23.8995

10.9 0.079 0.799 -20.0984

11 0.101 0.726 -17.1323

11.1 0.137 0.663 -13.6959

11.2 0.185 0.639 -10.7666

11.3 0.209 0.592 -9.04351

11.4 0.2 0.591 -9.41115

11.5 0.141 0.581 -12.2991

11.6 0.062 0.575 -19.3455

11.7 0.016 0.588 -31.3051

11.8 0.003 0.6 -46.0206

11.9 0.017 0.583 -30.7044

12 0.06 0.443 -17.365

12.1 0.074 0.388 -14.392

12.2 0.061 0.311 -14.1486

12.3 0.047 0.272 -15.2494

12.4 0.033 0.257 -17.8284

12.5 0.015 0.262 -24.8442

12.6 0.009 0.264 -29.3472

12.7 0.028 0.236 -18.5151

12.8 0.027 0.181 -16.5263

12.9 0.018 0.14 -17.8171

13 0.011 0.094 -18.6347

Radiation pattern

degrees current in µA

0 0.003

10 0.016

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

11.2 11.4 11.6 11.8 12 12.2 12.4

Series1

34

20 0.045

30 0.072

40 0.084

50 0.093

60 0.094

70 0.088

80 0.083

90 0.079

100 0.086

110 0.1

120 0.085

130 0.059

140 0.036

150 0.009

160 0.002


In both the antennas there is a good agreement between experimental and

simulated values with respect to return loss,bandwidth etc.

.. Addition of patches is the potential method to enhance the bandwidth of the

conventional microstrip antennas. For multi-band applications also, this is suitable


0

0.02

0.04

0.06

0.08

0.1

0.12

0 10 20 30 40 50 60 70 80 90 100110120130140150160170

Series1

35

of patches, such microstrip antennas can be designed for various applications. Gap-

coupling along with some other bandwidth enhancement techniques can be used

together to produce ultra large bandwidth, and the antennas can be designed for

various wideband applications.

PART 2

With the intension of getting still higher band width different antennas of different

mudra shapes as given below are simulated and the results are tabulated. Further

experimental investigations are to be carried out

Table 1 showing different mudras

Sl no

Name Pattern

1. Prana mudra

2. Apana Mudra

3. Jnana Mudra

4. Akasha

Mudra

5. Aditi Mudra

6. Eka Mudra

7. Mrigi Mudra

36

Table 2 showing the comparative result

Sl no Name Return loss in -dB

Res.Frequency in GHz

Band Width in GHz

% band width

Efficiency in%

Gain

1. Prana mudra 45 9.09 .5649 6.2 51.1 4.1

2. Apana Mudra 40 9.56 .577 6.0 45 3.3

3. Jnana Mudra 42 37 multy band

9.66 10.66

1.5 15 37 29

2.7 2.9

4. Akasha Mudra

43 9.59 .758 7.9 40 2.8

5. Aditi Mudra 39 9.58 .569 5.9 44.47 3.2

6. Eka Mudra 37 9.70 .473 4.8 46 3.45

7. Mrigi Mudra 37 9.45 .60 6.3 47 3.8

37

SUMMARY OF FINDINGS

1. The analysis reveals that in the gap coupling method Return loss increased to -

46 dB for 2.5mm gap. For circular patch it is only -33dB. And the bandwidth

increased by 16% The gap-coupling is the potential method to enhance the

bandwidth of the conventional microstrip antennas..

2. The systematic study of variation of return loss with the gap between the patches

reveals that Return loss decreases with the gap between the patches and reaches a

maximum of -46 dB for 2.5mm gap. For circular patch it is only -33dB.Band width

decreases with the gap, Resonance frequency varies with the gap.

3. Analysis revealed that addition of patches enhanced the bandwidth by nearly 16


the conventional microstrip antennas.

The empirical formula almost holds good for all trials within the experimental

errors. In coming days suitable theory can be developed which may agree very

well with the experimental results.

4. Analysis revealed that addition of patches enhanced the bandwidth by nearly130

percent.There is a good agreement between experimental and simulated values

with respect to return loss, bandwidth etc.

Addition of patches is the potential method to enhance the bandwidth of the

conventional microstrip antennas. For multi-band applications also, this is suitable


of patches, such microstrip antennas can be designed for various applications. Gap-

38

coupling along with some other bandwidth enhancement techniques can be used

together to produce ultra large bandwidth, and the antennas can be designed for

various wideband applications.

Further study

Experiments will be carried out with the above mudrashapes and results are

compared and further investigation is done to have ultra high band antenna.

39

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