Inset Fed Rectangular.pdf

8/14/2019 Inset Fed Rectangular.pdf

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International Journal of Emerging Technology and Advanced Engineering

Website: www.ijetae.com (ISSN 2250-2459, ISO 9001:2008 Certified Journal, Volume 3, Issue 7, July 2013)

126

Analysis of Electrical Parameters of Inset Fed RectangularMicro strip Patch antenna (RMPA) by Varying Inset Gap and

Inset WidthSwarna Pundir1, D. Arya2, Aruna Bansal3

1,3M.Tech Student, IET Alwar, Electronics and Communication Department2Associate Professor, IET Alwar, Electronics and Communication Department.

Abstract-- This paper investigate the dependency of

electrical properties of inset fed rectangular microstrip patch

antenna (RMPA) by varying inset width and inset gap for

proper impedance matching to achieve efficient operation.

The design strategy is optimized for 2.4 GHz rectangularshaped patch antenna using CST Micro stripes 2009 EMC

Edition. It has been observed the performance of patch

antenna depends more on inset gap between patch conductor

and inset fed line rather than inset length.

Keywords-- Inset- fed, Inset gap, Inset width, Inset fed Line,

Patch antenna, Resonance frequency

I. INTRODUCTIONA wireless communication system emphasis on

lightweight, compact and cost effective low profile

antennas for frequencies above100 MHz ( 3m).

Microstrip patch antenna rises as a good candidate meeting

these requirements due to its versatility of possiblegeometry and easy integrity with printed circuits. The

performance of a patch antenna depends upon their

geometrical shape, physical dimensions and properties of

the material used. Including all this the location and type of

feed also plays a vital role for improving its performances.

The inset feed antenna provides a method of impedance

control with a planer configuration [1-2].It is found that a

shifted Cos2 function works well for the inset-fed patch [3-

4]. The parameters of the shifted cosine function squared

depend on the inset width for a given patch and substrate

geometry [5]. Bandwidth of a patch antenna is a linear

function of substrate thickness tand increasing t to increase

bandwidth result in greater surface wave, spurious radiationand reduced directivity. In inset fed technique a notch is cut

on the edge of radiating patch to increase the matching for

better performance by controlling the input impedance

level.

This paper analyzes the variation of electrical properties

of a patch antenna with respect to inset width and inset gap

keeping the width of inset fed line constant.

II. DESIGN PROCEDUREBefore designing a Patch antenna we take consideration

of some basic facts like resonant frequency fr, kind of

model used for analysis, feeding method, shape and

dimensions of patch as well as substrate. So here thefris

2.4 GHz ,Transmission line model is used because of ease

and gives good physical insight yet has less accurate and it

is more difficult to model coupling[6].Feeding method used

is recessed microstrip-line feed, shape considered is

rectangular patch on GML 1000 with dielectric constant r= 3.2 and thickness (t) of substrate is .762mm.

III. DESIGN METHODOLOGY While adopting the design strategy we try to keep the

return loss as minimum as possible. Design procedure is

conventional based on existing literature, choosing r in

advance as dielectric of substrate are not easily available

which alongside also brings the thickness of the material

with itself.

IV. PATCH ANALYSISSteps:

1. Calculate Width W [7]

2. Calculate reff [9]

reff = + [ ]-1/2

for Wp / h>1

3. Calculate L i.e. normalized length[8]

= 0.412( )( )


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4. CalculateLP

= - 2L5. For calculating notch width we use equation [10]

= + Rearranging the above equation for

= 6. Calculating [11][12]

= ( )Tabulated values using above equations are shown inTable 1.

Table 1:

Physical dimensions of microstrip patch antenna

Operating frequency 2.4GHz

Dielectric constant 3.2 (GML-1000)

Length of the patch Lp 34.75 mm

Width of the patch

Wp

43.129 mm

Thickness (t) of the

Substrate

.762mm

Model for Analysis Transmission Line TLMSubstrate Length 39.4 mm

Substrate Width 47.7 mm

Fig .1 shows the patch design with inset-fed located along the width.

V.SIMULATION STRATEGYSimulation is carried in a way to find out the effect of

variation in inset-fed gap and inset fed length on the

electrical parameters of patch antenna. Feed line with a

fixed width is extended up to the edge of the patch.

If we cut a notch on the patch and extend the inset fed

line, the input resistance of the fed line is that of where thenotch has been cut out of the patch, this gives a good

impedance matching for better result.

Here two parameters i.e. Inset gap width (notch width)

and the Inset fed (notch length) is varied keeping one of the

parameter constant at a time. Starting from the non

radiating edge notch width set to 00mm to0.34mm,

0.35mm and.5mm. Repeating it for the notch length from

the calculated value of 7.5mm 0.5mm.The variation is

kept in small steps as a minute change can also be easily

observed in this process rather than using bigger variations.

VI. RESULT AND DISCUSSIONSummarizations of different model are shown in the

Table 2, showing the effects on all the electrical

parameters of microstrip patch antenna. Figure _and _

shows the simulated variation in return loss (S11) and

bandwidth for model C, G and K. As input impedance of

inset fed patch antenna depends primarily upon the inset

length d and to some extend at the inset gap between

patch conductor and inset line. These result shows that the

resonance frequency ,return loss and bandwidth is to some

extend depends upon the inset gap g and less on inset

length d. On comparing model no A, E, I with C,G,K, it is

easily seen that due to input impedance there is shift in S11,bandwidth and resonance frequency . One can be precise

for a selective resonance frequency with choosing aproper width gap.

VII. CONCLUSION For better analysis, input impedance of patch antenna

plays an important role as it will decide the performance of

an patch antenna. It can be easily concluded that impedance

matching depends more on inset gap rather than inset

length which in return affect the electrical parameters of a

microstrip antenna.

REFRENCES

[1] L.I.Basilio,M.A.Khayat,J.T.Williams and S.A. Long, TheDependence of the Input Impedance on Feed Position of Probe andMicrostrip Line-fed Patch Antenna,IEEE Trans.Antenna and

Propagation,Vol.AP-49,pp.45-47,Jan.2001.

[2] T.Samaras,A.Kouloglou ,and J.N.Sahalos, A note on the impedancevariation with feed position of a rectangular microstrip antenna,

IEEE Antennas and Propagation Magazine,vol.46,pp.90-

92,April2004.

[3] Y.Hu,E.J.Lundgren,D.R Jackson, J.T. Williams and S.A. Long, Astudy of the Input Impedance of the Inset fed Rectangular

Microstrip antenna as a function of notch depth and width,2005

AP-S International Symposium, Washington DC, July 2005.


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[4] Y.Hu, D.R. Jackson ,J.T.williams , and S.A.Long,A Designapproach for inset-fed rectangular microstrip antennas, AP-SInternational Symposium,pp.1494 july2006.

[5] M.A.Matin, A.I.Sayeed ,A Design for Inset-fed RectangularMicrostrip Patch Antenna, Wseas Transactions on Communication,Issue 1,Vol.9,Jan 2010.

[6] E.H Van Lil and A.R Van De Capelle ,Transmission Line Modelfor Mutual Coupling Between Microstrip Antennas,

IEEETrans.Antennas Propagat.,Vol AP-32,No.8,pp816-

821,Aug1984.

[7] I.J Bahl and P Bhartia, Microstrip Antenna, Artech House,Dedham.M.A, 1980.

[8] T.A.Milligan,Modern Antenna Design, McGraw-Hill Book Co.,New York ,1985

[9] C.A.Balanis, Advanced Engineering Electromagnetics,John Wiley &Sons, New York,1989

[10] M.A.Matin, A.I.Sayeed,,A Design Rule for Inset-fed RectangularMicrostrip Patch Antenna,,WSEAS Trans. on Communication, Issue

1,Vol.9,Jan 2010.

[11] A.G.Derneryd,A Theoretical Investigation of the RectangularMicrostrip Antenna Element,IEEE Trans.Antenna Propagat.,

Vol.AP-26,No.4,pp532-535 ,July1978

[12] K.R.Carver and J.W.Mink,Microstrip Antenna Technology,IEEETrans. Antenna Propagat., Vol.AP-29, No.1, pp2-24, Jan 1981

Simulation Analysis

Table 2

Summarization of simulated result

Inset Feed Patchl

No.

Inset

Gap

Inset

Length

Return Loss in

dB

Resonance

frequency

(GHz)

A.E

(dB)

R.E

(dB)

Directivity

in

( dBi)

Gain

in

( dBi)

Band Widt

In

% age

W

(mm)

Lf

(mm)

g

(mm)

d

(mm)

2 2 5B 00 7 -13.261 2.374 65.266 71.881 6.199 4.346 2.358

4B .34 7 -25.383 2.394 69.307 69.677 6.174 4.582 3.592

3B .35 7 -24.591 2.394 69.338 69.725 6.175 4.585 3.550

2B .5 7 -22.560 2.413 68.571 69.530 6.164 4.526 3.522

2 2 5 00 7.5 -13.416 2.373 65.098 71.796 6.195 4.330 2.444

4 .34 7.5 -22.641 2.401 69.344 69.686 6.171 4.587 3.4983 .35 7.5 -22.635 2.402 69.748 69.748 6.173 4.587 3.538

2 .50 7.5 -21.029 2.406 69.073 69.784 6.166 4.559 3.408

2 2 5A 00 8 -13.427 2.373 65.155 71.898 6.196 4.336 2.444

4A .34 8 -17.132 2.396 68.162 69.582 6.169 4.505 3.338

3A .35 8 -17.039 2.397 68.217 69.654 6.173 4.512 3.380

2B .5 8 -15.580 2.398 67.683 69.649 6.172 4.477 3.439

Simulated Result

Fig 2: return loss for patch 3A Fig 2A: radiation patern for patch 3A


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Fig 7: return loss for patch 5B Fig 7A: radiation patern for patch 5B

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Inset Fed Rectangular.pdf