Multi Resonant Stacked Micro Strip Patch Antenna Designs ...ijarcet.org/wp-content/uploads/IJARCET-VOL-3-ISSUE-10-3577-3585.pdf · s hape. H ow e vr, MPA su f m di aan ge hey

International Journal of Advanced Research in Computer Engineering & Technology (IJARCET)

Volume 3 Issue 10, October 2014

3577

ISSN: 2278 – 1323 All Rights Reserved © 2014 IJARCET

Multi Resonant Stacked Micro Strip Patch

Antenna Designs for IMT, WLAN &

WiMAX Applications

Tejinder Kaur Gill, Ekambir Sidhu

Abstract: In this paper, stacked multi resonant slotted

micro strip patch antennas (MPA) have been proposed

which are suitable to be used for GSM, WLAN

standard and WiMAX applications. The antennas

have been designed using substrate of FR4 material. In

the designed antennas, substrates having different

thickness have been used. The performance of designed

antenna has been observed by comparing without air

gap between the stacks with same antenna having air

gap of 0.8 mm between two stacks. It has been observed

that air gap in stacking results in increase of antenna

impedance bandwidth. The bottom stack of designed

antenna has a radiating patch of circular shape and the

patch on the upper stack is of rectangular shape. The

antenna has a feed line which is connected to circular

patch. The designed antennas have a defected ground

structure in order to improve the antenna performance.

The antenna performance has been measured in terms

of antenna parameters such as impedance bandwidth,

Return loss, antenna impedance, VSWR and

Directivity. The designed antenna results have been

simulated in CST Microwave Studio 2010. The

practically designed antennas have been tested

successfully by using Network analyzer E5071C. It has

been observed that the practical results closely match

with theoretical results.

Index Terms— Defected ground structure, Directivity,

Micro strip patch antenna, Multi resonant air gap stacked

antenna, Return loss (S11), VSWR.

Tejinder Kaur Gill, Department of Electronics & Communication

Engineering, Punjabi University Patiala., India ,+919041806381

Ekambir Sidhu, Department of Electronics and

Communication Engineering, Punjabi University, Patiala, India, 84275299711.

I. INTRODUCTION

Microstrip antenna, also known as printed circuit antenna

or patch antenna is suitable for conformal and low profile

applications. The Microstrip Patch Antenna has advantage

of low cost and weight, design flexibility and ease of

installation [4]. The radiating elements together with feed

line are photo etched on a thin dielectric sheet on a ground

plane. The patch can be square, rectangular or circular in

shape. However, MPA suffers from disadvantage that they

have narrow bandwidth. Extensive research has been

carried out to overcome the band width problem in recent

years and many techniques have been suggested and

implemented to achieve the desired wide band

characteristics [2]-[3]. One of these techniques is stacked

antennas, realizing dual frequency operation with two

resonant frequencies separated by certain range [8]-[9].

Stacked patch antenna is a kind of microstrip antenna

which consists of two printed antennas. The lower

patch is called driven patch and another patch is

parasitically coupled to driven patch. To produce

broadband responses, the selection of the substrate of the

first layer is very important.

.

Section II (Antenna Geometry) explains the geometry of

antenna. The top view, bottom view and dimensions of

substrate, patch, slots on the patch and ground plane are

listed in section II.

Section III (Results and Discussions) describes the

simulated results obtained by using CST MWS (2010)

which includes Return loss (S11), Directivity, Gain at

corresponding resonant frequencies, VSWR and Smith

chart plots.

Section IV (Experimental verification) indicates the top and

bottom view of practically designed antenna and describes

practical results obtained by testing the practically designed

antenna using E5071C ENA series Network Analyzer.



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Section V (conclusion) explains both simulated theoretical

results and practical results in terms of return loss at

corresponding resonant frequencies and bandwidth, along

with list of applications in which designed antenna

can be used.

II . ANTENNA GEOMETRY

Fig. 1 shows the top view of the bottom stack of the

antenna. The Fig1 shows circular slotted patch, excited

by feedline of suitable width. Fig. 2 represents the top

view of upper stack. Fig. 3 represents the bottom view of

stacked antenna. The ground has been designed at the

bottom of the lower stack which has been partially

reduced. The antenna has been fabricated using FR4 as an

substrate with dielectric constant of 4.4.The height of

lower substrate is 1.57mm and that of upper substrate is

0.8mm.The feedline is designed in such a way that antenna

will have 50 ohm resistance matched with the port

impedance for maximum power transfer from port to

patch. Fig. 4 shows the stacked air gap antenna with all

the dimensions same except the air gap is present. The

dimensions of substrate, patch, feed, slots cut on patch and

ground are listed in Table. 1

NOTE: The dotted lines in Fig. 3 represent the projection

of patch and feedline on ground. NOTE: The air gap of 0.8mm has been maintained by

inserting a 0.8 mm FR4 sheet between the two stacks at

their edges. This can be cleared from the Fig. 9 (c)

Fig. 1Top View of bottom stack of antenna

TABLE 1. ANTENNA PARAMETERS

Antenna Parameter Specification

Length of substrate (Ls) 60mm

Width of substrate (Ws) 60 mm

Radius of lower patch (R1) 18.8mm

Radius of circular slot (R2) 10.8mm

Length of feed (Lp) 112mm

Width of feed (Wp) 5.6mm

Length (L1) 22mm

Length (L2) 21mm

Length (L3) 20mm

Width (W1) 13.2mm

Width (W2) 5.6mm

Width (W3) 4mm

Width (W4) 2mm

Width (W5) 2mm

Width (W6) 2mm

Length of upper substrate (LUs) 60mm

Width of upper substrate (WUs) 60mm

Length of upper patch (LU1) 25mm

Width of upper patch (WU1) 11.6mm

Length of ground (Lg1) 12mm

Width of ground (Wg4) 60mm

Length of slot on ground (Lg5) 3mm

Width of slot on ground (Wg5) 6.4mm

Length (LU2) 30mm

Width (WU1) 24.2mm

Thickness of upper stack ( T1) 0.8mm

Thickness of lower stack ( T2) 1.57mm

Air gap (Ag) 0.8mm

Fig. 2Top view of stacked antenna



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Fig. 3Bottom View of stacked antenna

Fig. 4 View of stacked antenna with air gap

III. RESULTS AND DISCUSSIONS

The designed stacked antenna have been simulated using CST Microwave Studio 2010 and the performance of the antenna has been analyzed in terms of return loss, VSWR, radiation pattern, directivity, impedance and gain. The experimental results have been also obtained using E5071C ENA series Network Analyzer and it

has been concluded that the practical results closely matches with the simulated theoretical results. Fig. 5 represents the simulated results of return loss (S11) for designed stacked antenna without

any air gap. It has been observed that the return loss is -43.258 dB at 1.7245GHz, -24.473 dB at 2.734 GHz, -22.169 dB at 3.385 GHz and -37.41 dB at 5.047GHz. The simulated bandwidth of the proposed antennas is 2.2887 GHz.

Fig. 6 represents the simulated results of return loss (S11) for designed stacked antenna without any air gap.

It has been observed that the return loss is -34.70 dB at 1.8086 GHz, -25.418 dB at 2.944 GHz, -21.32 dB at -3.2072 GHz, -20dB at 4.721 GHz and -30.774 dB at 5.310GHz. The simulated bandwidth of the proposed antennas is 2.62841 GHz.

Fig. 5Return loss of stacked MPA without air gap

Fig. 6 Return loss of stacked MPA with air Gap

The directivity of stacked antenna without air gap at

resonant frequencies have been obtained and analyzed. Fig. 5(a), Fig. 5(b), Fig. 5(c) and Fig. 5(d) shows the 3D

plot of directivity of slotted MPA at resonant frequencies

of 1.7 GHz, 2.7 GHz, 3.4 GHz and 5.0 GHz,

respectively. The directivity is 2.038 dBi at 1.7 GHz,

2.804 dBi at 2.7 GHz, 4. 2 7 9 d Bi a t 3. 4 G H z and

4.307 dBi at 5.0 GHz. It has been observed that

directivity is better for higher resonant frequencies than

lower frequencies.

Fig. 5(e), Fig. 5(f), Fig. 5(g), Fig. 5(h) illustrates the 3D

plot of gain for slotted MPA at resonant frequencies

of 1.7 GHz, 2.7 GHz, 3.4 GHz and 5.50 G H z

respectively. The 3D plot shows that the gain is 2.992 dB

at 1.7 GHz, 3.772 dB at 2.7 GHz, 4.290dB at 3.4 GHz

and 5.255 dB at 4.307GHz.



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Fig. 5(a) 3D plot of Directivity of stacked MPA

without air gap at 1.7 GHz

Fig. 5(b) 3D plot of Directivity of stacked MPA


Fig. 5(c) 3D plot of Directivity of stacked MPA


Fig. 5(d) 3D plot of Directivity of stacked MPA

without air gap at 5.04 GHz.

Fig. 5(e) 3D plot of Gain of stacked MPA without

air gap at 1.7 GHz

Fig. 5(f) 3D plot of Gain of stacked MPA without

air gap at 2.7 GHz

Fig. 5(g) 3D plot of Gain of stacked MPA without

air gap at 3.4 GHz

Fig. 5(h) 3D plot of Gain of stacked MPA without

air gap at 5.0 GHz Similarly, the antenna with air gap has been designed

and the directivity at resonant frequencies has been



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obtained and analyzed. Fig. 6 (a), Fig. 6(b), Fig. 6(c),

Fig. 6(d), and Fig. 6(e) shows the 3D plot of

directivity of slotted MPA at resonant frequencies of

1.8 GHz, 2.9 GHz, 3.2 GHz, 4.7 GHz and 5.3GHz

respectively. The directivity is 2.110 dBi at 1.8 GHz,

2.139 dBi at 2.9 GHz, 4. 1 3 0 d Bi a t 3 . 2 G H z, 3.710 dBi at 4.7 GHz and 4.064 dBi at 5.3 GHz.

Fig. 6(f), Fig. 6(g), Fig. 6(h), Fig. 6(i) and Fig 6(j)

illustrates the 3D plot of gain for slotted MPA w i t h

a i r g a p at resonant frequencies 1.8 GHz, 2.9 GHz,

3.2 GHz, 4.7 GHz and 5.3 GHz respectively. The 3D

plot shows that the gain is 2.832 dB at 1.8 GHz, 3.748

dB at 2.9 GHz, 5.073 dB at 3.2 GHz, 4.612 dB at 4.7

GHz and 4.977 dB at 5.3 GHz

Fig. 6(a) 3D plot of Directivity of stacked MPA with

air gap at 1.8 GHz

Fig. 6(b) 3D plot of Directivity of stacked MPA with

air gap at 2.9 GHz

Fig. 6(c) 3D plot of Directivity of stacked MPA with

air gap at 3.2 GHz

Fig. 6(d) 3D plot of Directivity of stacked MPA

with air gap at 4.7 GHz

Fig. 6(e) 3D plot of Directivity of stacked MPA

with air gap at 5.3 GHz



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Fig. 6(f) 3D plot of Gain of stacked MPA with air

gap at 1.8 GHz

Fig. 6(g) 3D plot of Gain of stacked MPA with air

gap at 2.9 GHz

Fig. 6(h) 3D plot of Gain of stacked MPA with air

gap at 3.2 GHz

Fig. 6(i) 3D plot of Gain of stacked MPA with air

gap at 4.7GHz

Fig. 6(j) 3D plot of Gain of stacked MPA with air

gap at 5.3 GHz

Fig. 7(a) and Fig. 7(b) depicts the simulated VSWR plot

for stacked MPA without air gap and with air gap

respectively. The required value of VSWR should be

less than 2. Fig. 7(a) shows that value of VSWR for

stacked MPA without air gap is less than 2 in the

operating frequency range of 1.57 GHz to 1.83 GHz, 2.5

GHz to 3.1 GHz, 4.2 GHz to 5.67 GHz. Fig. 7(b) shows

that value of VSWR for stacked MPA with air gap is

less than 2 in the operating frequency range of 1.64 GHz

to 1.965 GHz, 2.75 GHz to 3.46 GHz, 4.35 GHz to 6.03

GHz.

Fig. 7(a) VSWR plot of stacked MPA without air gap

Fig. 7(b) VSWR plot of stacked MPA with air gap



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Fig. 8(a) and Fig. 8(b) indicates Smith chart plot for slotted

MPA without air gap and Smith chart plot for slotted

MPA with air gap. The Smith Chart plot indicates the

variation in impedance of antenna with frequency. The

value of impedance should lie near 50 ohms in order to

perfectly match the port with the antenna. The antenna

impedance for both designed slotted MPA antenna

without air gap and with air gap is 50 Ω.

Fig. 8(a) Smith chart plot of stacked MPA without air gap

Fig. 8(b) Smith chart plot of stacked MPA with air gap

IV.EXPERIMENTAL VERIFICATION

The proposed antenna has been physically

designed and the top and bottom view of

practically designed antenna are shown in Fig. 9(a)

and Fig. 9(b), respectively. The Fig. 9(c)

represents the air gap between two stacks. The

designs are tested using E5071C ENA series

Network Analyzer. The practically analyzed

results of slotted MPA are shown in Fig. 10(a)

and Fig. 10(b). It has been observed from Fig.

10(a) that the practical results of designed MPA

without any air gap have return loss of -38.89 dB at

1.79 GHz, -24.09 dB and -29.85 dB at 2.78 GHz

and 5.10 GHz respectively. The bandwidth

obtained from practical results of designed MPA

is 2.57 GHz. Similarly it has been observed from

Fig. 10(b) that the practical results of designed

MPA with air gap have return loss of -33.536

dB at 1.81 GHz, -27.429 at 2.9 GHz, -24.77 at

3.25 GHz, -19.691dB and -29.852 dB at -4.6384

GHz and 5.463 GHz, respectively. The bandwidth

obtained from practical results of designed MPA is

3.042GHz.

Fig. 9(a) Top view of designed stacked MPA

Fig. 9(b) Bottom view of designed stacked MPA

Fig. 9(c) View of air gap of stacked microstrip

antenna with air gap



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Fig. 10(a) Experimental result of MPA without air

gap

Fig. 10(b) Experimental result of MPA with air gap

V. CONCLUSION

From the above discussion, it can be concluded that the

stacked microstrip patch antenna without air gap has

bandwidth of 2.3554 GHz with operating frequency

range between 1.5GHz to 5.7 GHz .The VSWR for

stacked microstrip patch antenna without air gap is

less than 2 in the operating frequency range of 1.5

GHz to 5.7 GHz.

For the stacked microstrip antenna with air gap of

0.8mm, it can be concluded that bandwidth is 2.6644

GHz with operating frequency range between 1.63 to

6.004 GHz. The VSWR for stacked microstrip patch

antenna is less than 2 in an operating frequency range

between 1.63GHz to 6.004 GHz. The simulated results

of the designed stacked antenna closely match with

practical results. It has been observed that the practical

results obtained from designed stacked MPA without air

gap has bandwidth of 2.57 GHz having frequency range

from 1.51 GHz to 5.63 GHz and the designed stacked

antenna with air gap has practical results with

bandwidth from 1.62 GHz to 6.18 GHz. The designed

antenna w i t h o u t a i r g a p is suitable to be used for

IMT only (2.69 GHz to 3.57 GHz, 4.333 GHz to

5.63 GHz) and the antenna with air gap is suitable for

GSM (1.62 GHz to 1.98 GHz), WLAN standard (4.37

GHz to 6.18 GHz) and WiMAX (3.4 GHz to 3.69 GHz,

5.25 GHz to 5.85 GHz) applications [1].

CONCLUSION TABLE:

PARAMETERS WITHOUT AIR GAP

WITH AIR GAP

Bandwidth Range (Theoretically)

Between 1.5 GHz to 5.7 GHz


Bandwidth Range (Practically)



VSWR Less than 2 Less than 2

Impedance

(ohm)

50 50

APPLICATION IMT only GSM, WLAN,WiMax

REFERENCES

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[4] J. l BahI & Bharta P., Microstrip Antennas,

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http://ieeexplore.ieee.org/Xplore/defdeny.jsp



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[8] S.A Long & Walton M.D, A Dual-frequency

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[9] T.M Au and K M Luk, Effect of

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Documents

Multi Resonant Stacked Micro Strip Patch Antenna Designs ...ijarcet.org/wp-content/uploads/IJARCET-VOL-3-ISSUE-10-3577-3585.pdf · s hape. H ow e vr, MPA su f m di aan ge hey