design of dual band slotted microstrip patch …slotted frequency reconfigurable microstrip patch...

International Journal of Applied Engineering Research ISSN 0973-4562 Volume 13, Number 11 (2018) pp. 10082-10093

© Research India Publications. http://www.ripublication.com

10082

Design of Dual band Slotted Microstrip Patch Antenna for Wi-Fi &

Wi-Max Applications

1Mr. Prasanna Paga,2Dr. H.C.Nagaraj,3Dr.T.S.Rukmini

1Research scholar, NREA, Nitte Meenakshi Institute of Technology, Yelahanka, Bangalore, India. 2Professor & Principal, Department of Electronics and Communication Engineering, NREA,Nitte Meenakshi

Institute of Technology, Yelahanka, Bangalore, India. 3Professor, Department of Electronics and Communication Engineering, Nitte Meenakshi Institute of

Technology, Yelahanka, Bangalore, India.

Abstract

This paper highlights the proposed design for a dual band

slotted frequency reconfigurable microstrip patch antenna fed

through a 50Ω coaxial feed using inset type of a feeding

system over the FR4 substrate for resonating between Wi-Fi

and Wi-Max frequency bands. The patch antenna is proposed

to tune between two frequencies i.e. Wi-Fi frequency

(2.4GHz) and the Wi-Max (3.5GHz) with the help of slots.

The proposed structure resulted in a gain of 1.94dBi and

3.31dBi for the lower and the upper frequency bands

respectively.the measured radiation patterns were Omni

directional in the higher band.

Keywords: Wi-Fi, Wi-Max, slotted,

INTRODUCTION

Traditionally wireless systems were designed for single

predefined mission. Therefore, the antennas used in these

systems also possessed some fixed parameters such as

frequency band, radiation pattern, polarization, and gain.

Recently reconfigurable antennas (RAs) have gain

tremendous research interest for many different applications,

for example, cellular radio system, radar system, satellite

communication,airplane, and unmanned airborne vehicle

(UAV) radar, smart weapon protection. In mobile and satellite

communications, reconfigurable antennas are useful to

support a large number of standards (e.g., UMTS,

Bluetooth,WiFi, Wi-MAX, DSRC) .A single multifunctional

antenna can replace multiple single functional antennas.In [6]

various types of Reconfigurable Antennas and their realization

using electronic switches such as PIN diodes have been

discussed.However such designs suffer from biasing

problems. planar antennas have been most widely used in

wireless communication systems, especially in wireless local

area network (WLAN), Worldwide Interoperability for

Microwave Access (WiMAX) and Long Term Evolution

(LTE) applications. In order to satisfy the

WLAN/WiMAX/LTE standards, multiband antennas which

operate at 2.4–2.484 GHz/5.15–5.825 GHz for WLAN, 2.5–

2.69 GHz/3.4–3.69 GHz/5.25–5.85 GHz for WiMAX are

required where in independent tuning can be obtained for a

particular frequency bands of interest In [1], a dual band

slotted antenna with Co-planar waveguide feed has been

presented for WLAN and Wi-Max applications.The structure

resulted in a gain of 2.4dBi and 2.7dBi and a bandwidth of

400MHz and 1.02GHz for the lower and the upper frequency

bands respectively.The structure has been simulated on a FR4

substrate of permittivity 4.4 and thickness 1mm.In[2], a tri

band slotted Bow tie antenna has been designed targeting

2.5GHz, 3.5GHz and 5.5GHz wireless applications. The

structure resulted in a Gain of 2.4dB, 3.0dB and 3.55dB for

the lower, middle and the upper frequency bands

respectively.The structure has been simulated on a FR4

substrate of permittivity 4.4.The peak boresight gains reported

were negative for all the three frequency bands of interest. In

[3], a tri band antenna targeting Wireless LAN and WiMAX

frequency bands were presented The structure resulted in

Gains of about 1dBi,2dBi and 1.25dBi for the lower, middle

and the upper frequency bands respectively.The measured

radiation patterns were nearly omni directional under azimuth

plane and were characterized by the presence of nulls under

elevation plane.In [4], a triband antenna targeting WLAN and

Wi-MAX applications were presented using a Dual U shaped

slot. The structure has been simulated on a FR4 substrate of

permittivity 4.4.The fractional bandwidths reported were

3.14%, 4.96% and 2.56% for the lower, middle and the upper

frequency bands respectively. The simulated radiation patterns

were directional. In[5], a dual band antenna has been

fabricated on a FR4 substrate of permittivity 4.4 targeting

WLAN frequency bands. The structure resulted in two

different resonant frequencies of 2.45GHz and 5.8GHz.The

peak gains reported were 1.6dBi and 2.33dBi for the lower

and the upper frequency bands respectively. The measured

radiation pattern were characterized by the presence of nulls

under both the lower and the upper frequency bands

respectively. In [6], a comparative analysis of various

reconfigurable and multiband antenna concepts was presented.

The different techniques for realizing Multiband Antennas

such as PIN diodes, MEMS switches, and varactors were

discussed. In [7], a dual band antenna based on metamaterial

planar structure operating in S band and C band is designed

and developed for Space and Radar communication

Applications using CSRR in the Ground plane. The structure

has been designed on a FR4 substrate of permittivity 4.4 with

a dimension of 21.7mm X 20.4mm with a substrate thickness

of 1.6mm along with Microstrip line feeding technique. It

mailto:[email protected]

mailto:principal@nmit.



10083

resonates at 2.7GHz, 7.5GHz with the return loss of -17.27dB,

-29.63dB, respectively with a -10dB impedance Bandwidth of

6.8GHz .The average Gain of the Antenna is 5.82dB.In [8], a

metamaterial based dual band Antenna has been proposed for

Wi-Max Application using CSRR.The radiating structure

resonates at two different frequencies of 3.5GHz and 5.5GHz

.The radiating structure resulted in a return loss of -24.5dB,-

31dB,a Bandwidth of 112.1MHz and 92.1MHz for both the

lower and the upper bands respectively. The structure has

been designed on a Rogers substrate of permittivity 2.2 and

resulted in a Gain of 4.5dBi and 5.0dBi for both the lower and

the upper bands respectively.In [9], a multiband monopole

antenna has been designed on a Rogers substrate of

permittivity 3.23 using CSRR The structure resulted in a gain

of -1.0 dBi,1.0dBi and 4.0 dBi, a return loss value of -25dB,-

15.0dB and -20.0dB respectively for 2.4GHz,3.5GHz and

5.2GHz frequency bands respectively. The radiating structure

resulted in a Bandwidth of 440MHz, 200MHz and 200 MHz

for the lower, middle and the upper bands respectively.In [10],

a dual band patch antenna is designed by loading a U-slot

metamaterial structure on the surface of the rectangular patch

.The structure has been designed on a FR4 substrate with a

thickness of 6mm. The structure resulted in a resonant

frequency of 3.58GHz and 5.74 GHz with a return loss value

of -16.0dB,-12.5dB and a Bandwidth of 490MHz and 650

MHz for the lower and the upper frequency bands

respectively.

ANTENNA DESIGN

Figure 1(a) Geometrical specifications of the slotted Antenna

in HFSS.

Figure 1(b) length of the symmetrical slots of the slotted

antenna using inset feeding technique.

Figure 2 (a) Snapshot of the (b) the Ground plane view Dual

band Antenna on FR4

METHODOLOGY

In the proposed work, a dual band Antenna has been designed,

simulated and Fabricated on a FR4 substrate of permittivity

4.4 and thickness 1.6mm to tune between Wi-Fi (2.4GHz) and

Wi-Max 3.5GHz Frequency band. The length and the width of

the patch antenna are selected so as to tune to 2.4GHz

frequency band.The length of the patch has been kept at half

the guide wavelength corresponding to 2.4GHz.Two

symmetrical slots of length 3.5mm by 8.5mm have been cut

on the surface of the patch so as to tune to 3.5GHz frequency

band of interest. Inset type of feeding technique has been

employed for impedance matching between the port and the

antenna.The length of the inset feed is kept at 10mm from the

edge of the patch to get the required 50 ohms impedance

point.

DESIGN EQUATIONS

𝐿 =𝑐

2𝑓𝑟√𝜀𝑟𝑒𝑓𝑓− 2∆𝐿 (1)

Lp = L = Length of the patch



10084

fr = resonant frequency corresponding

to 2.4GHz frequency band

∆𝐿 = patch length extension

h=substrate thickness

W= width of the patch

ϵreff = effective permittivity ofthe substrate

𝜖𝑟𝑒𝑓𝑓 =𝜖𝑟+1

2+ (

𝜖𝑟−1

2) ∗ (1 + 12 (

ℎ

𝑊))

−1

2 (2)

𝑓1 =𝑐

√𝜀𝑟𝑒𝑓𝑓×4×𝑙𝑠𝑙𝑜𝑡1 (3)

Where

f1 = Resonant Frequency corresponding to 3.5GHz .

lslot1 = slot length corresponding to 3.5GHz.

∆𝐿 = ℎ ∗ 0.412 ∗ (𝜖𝑟𝑒𝑓𝑓+0.3)(

𝑊

ℎ+0.264)

(𝜖𝑟𝑒𝑓𝑓−0.258)(𝑊

ℎ+0.8)

(4)

SIMULATION AND MEASURED RESULTS

Figure 3. Simulated return loss plot of the slotted Antenna resonating at 2.3GHz and 3.5 GHz indicating a value of -13.68dB and

-25.2dB for the lower and the upper frequency bands respectively as indicated by markers m1 and m2 on FR4 substrate of

permittivity 4.4. The Horizontal Axis represents the Frequency(in GHz) while the vertical axis represents the reflection co-

efficient(in dB).

1.00 1.50 2.00 2.50 3.00 3.50 4.00Freq [GHz]

-30.00

-25.00

-20.00

-15.00

-10.00

-5.00

0.00

dB

(S(1

,1))

DESIGN2return_loss

m1

m2

Curve Info

dB(S(1,1))Setup1 : Sw eep

Name Freq X Y

m1 2.3648 2.3648 -13.3467

m2 3.5628 3.5628 -25.2181



10085

Figure 4. Simulated VSWR plot of the slotted Antenna resonating at 2.3GHz and 3.5 GHz indicating a value of 1.47 and 1.11 for

the lower and the upper frequency bands respectively as indicated by markers m1 and m2 on FR4 substrate of permittivity 4.4.The

Horizontal axis represents the Frequency(in GHz) while the vertical axis represents the normal value of vswr.

Figure 5. Simulated bandwidth of the slotted antenna resonating at 2.4GHz indicating a value of 0.038GHz..The -10dB

impedance bandwidth is extending from 2.34GHz to 2.38GHz..The Horizontal axis represents the Frequency(in GHz) while the

vertical axis represents the reflection coefficient(in dB).

1.00 1.50 2.00 2.50 3.00 3.50 4.00Freq [GHz]

0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00V

SW

R(1

)

DESIGN2VSWR plot of the Antenna

m1 m2

Curve Info

VSWR(1)Setup1 : Sw eep

Name Freq X Y

m1 2.3719 2.3719 1.4768

m2 3.5628 3.5628 1.1160

m1

m2

m1 m2



10086

Figure 6. Simulated bandwidth of the slotted antenna resonating at 3.5GHz indicating a value of 0.08GHz.The -10dB impedance

bandwidth is extending between 3.52GHz to 3.6GHz..The Horizontal axis represents the Frequency(in GHz) while the vertical

axis represents the reflection coefficient(in dB).

Figure 7. Simulated radiation pattern of the antenna resonating at 3.5GHz under H plane indicating a peak gain of 2.7dB. The

radial axis represents the Antenna Gain (in dB) while the angular axis represents the scan angle (in degrees)

-35.00

-30.00

-25.00

-20.00

-15.00

-10.00

-5.00

0.00

90

60

30

0

-30

-60

-90

-120

-150

-180

150

120

DESIGN2Radiation Pattern 5

m1

Curve Info

dB(GainTotal)Setup1 : LastAdaptiveFreq='3.6GHz' Phi='0deg'

Name Theta Ang Mag

m1 50.0000 50.0000 2.7168



10087

Figure 8. Simulated radiation pattern of the antenna resonating at 3.5GHz under E plane indicating a peak boresight gain of -7dB

under E plane. The radial axis represents the Antenna Gain (in dB) while the angular axis represents the scan angle (in degrees)

Figure 9. Simulated radiation pattern of the antenna resonating at 2.4GHz under H plane indicating a peak boresight gain of

2.34dB. The radial axis represents the Antenna Gain (in dB) while the angular axis represents the scan angle (in degrees)

-34.00

-28.00

-22.00

-16.00

-10.00

90

60

30

0

-30

-60

-90

-120

-150

-180

150

120


m1 Curve Info


Name Theta Ang Mag

m1 360.0000 -0.0000 -7.0175

-33.00

-26.00

-19.00

-12.00

-5.00

2.00

90

60

30

0

-30

-60

-90

-120

-150

-180

150

120


m1Curve Info


Name Theta Ang Mag

m1 360.0000 -0.0000 2.3426



10088

Figure 10. Simulated radiation pattern of the antenna resonating at 2.4GHz under E plane indicating a peak boresight gain of

2.34dB. The radial axis represents the Antenna Gain (in dB) while the angular axis represents the scan angle (in degrees)

Figure 11. Measured radiation pattern of the slotted Antenna on FR4 substrate (permittivity 4.4) indicating a peak boresight gain

of 3.31dB under E plane at 3.5GHz, as shown by marker m1.The radial axis represents the Gain (in dB) while the angular axis

represents the scan angle( in degrees).

-33.00

-26.00

-19.00

-12.00

-5.00

2.00

90

60

30

0

-30

-60

-90

-120

-150

-180

150

120


m1Curve Info


Name Theta Ang Mag

m1 360.0000 -0.0000 2.3426



10089


of 3.14dB under H plane at 3.5GHz, as shown by marker m1.The radial axis represents the Gain (in dB) while the angular axis



of 2.63dB under E plane at 2.4GHz, as shown by marker m1.The radial axis represents the Gain (in dB) while the angular axis




10090

Figure 14. Measured radiation pattern of the slotted Antenna on FR4 substrate of permittivity 4.4)indicating a peak boresight

gain of 1.94dB under H plane at 2.4GHz, as shown by marker m1.The radial axis represents the Gain (in dB) while the angular

axis represents the scan angle( in degrees).

Figure 15. Measured bandwidth of the slotted antenna resonating at 4.1GHz (marker 2). The -10dB impedance bandwidth is

extending between 3.94GHz to 4.43GHz as indicated by markers 1 and 3 giving a bandwidth of 0.49GHz..The Horizontal axis

represents the Frequency(in GHz) while the vertical axis represents the nominal value of the standing wave ratio.



10091

Figure 16. Measured return loss plot of the antenna resonating at 2.6GHz (marker 1) and 4.1GHz (marker 2) indicating a value of

-9.0dB and -44.0dB as shown by markers 1 and 2. The Horizontal axis represents the Frequency (in GHz) while the vertical axis

represents the reflection coefficient (in dB).

Figure 17. Measured VSWR plot of the antenna resonating at 2.6GHz (marker 1) and 4.1GHz (marker 2) indicating a value of

2.11 and 1.02. The Horizontal axis represents the Frequency (in GHz) while the vertical axis represents the normal value of vswr.



10092

RESULTS AND DISCUSSIONS

Table 1. Comparison between the simulated and measured value of the Dual band Slotted Microstrip patch Antenna

simulated on a FR4 substrate (εr=4.4 & thickness 1.6mm) for resonating between Wi-Fi & Wi-Max

Sl No Antenna parameters Simulated Measured

1 Resonant Frequency 2.36GHz 3.5GHz 2.6GHz 4.1GHz

2 Return Loss -14.3dB -25.2dB -9.0dB -40.02dB

3 Bandwidth 38.0MHz

(2.34GHz to 2.38GHz)

80.0MHz

(3.524GHz to 3.609GHz)

0 490MHz

(3.9GHz to 4.43GHz)

4 VSWR 1.47 1.18 2.13 1.02

4 Gain 2.34dB

(E & H )

2.7 dB(H)

-7.01dB(E)

2.63dB(E)

1.94dB(H)

3.31dB(E)

3.14dB(H)

Figure 6.19 Comparison of the Simulated and measured Antenna performance parameters using FR4 substrate for Resonating

between Wi-Fi(2.4GHz) and Wi-Max(3.5GHz).

RESULTS AND DISCUSSIONS

The Results of the slotted antenna have been reported in Table

1.The simulated return loss values were close to -14.3 dB & -

25.25dB in the lower and upper frequency bands respectively

indicating that the antenna radiates more efficiently in the

higher band when compared to lower Frequency band of

interest. The simulated vswr values were close to 1.47 in the

lower band as against 1.1 in the higher band indicating a poor

impedance matching in the lower Frequency band of interest.

The simulated and the measured Gains agree well. The lowest

reported measured Gain were 1.94dB under H plane at

2.4GHz while the highest reported Gain were 3.31dB under E

planes at the upper band. The measured Gain variation was

between the range of 1.94dB to 3.31 dB across both the bands

.The measured Bandwidths reported were 0 MHz and

490MHz for the lower and the upper frequency bands

respectively.The measured bandwidths were high in the upper

band when compared to lower band. The measured radiation

pattern were characterized by the presence of nulls in both the

upper and the lower frequency bands of interest. The

measured gains were comparatively higher when compared

with simulated across both the frequency bands of interest.

CONCLUSION

The Antenna resonates weakly in the Wi-Fi band when

compared to the Wi-Max band.The measured peak Gains

were in the range of 1.94dB to 3.31dB. The measured adiation

patterns were nearly omnidirectional in the upper band when

compared to the lower frequency band of interest.

-40

-35

-30

-25

-20

-15

-10

-5

0

5

10

Simulated (2.4 GHz)

Simulated (3.5GHz)

Measured (2.4 GHz)

Measured (3.5GHz)



10093

ACKNOWLEDGMENT

The Authors would like to thank Dr.Chandrika Sudheendra

Group Director,ADE and Mr.Diptiman Biswas Scientist

F,FTTT division ADE,DRDO for having permitted to carry

out Antenna characterization and measurement of radiation

pattern in the Anaechoic Chamber.

REFERENCES

[1] W. Hu, Y. Z. Yin, S. T. Fan, J. Y. Deng, M. Zhang,

“Compact CPW-Fed Square Slot Antenna For Dual-Band Operation” Progress In Electromagnetics

Research Letters, Vol. 20, 165–173, 2011.

[2] Ming-Tien Wu and Ming-Lin Chuang, “Multi-broadband Slotted Bow-Tie Monopole Antenna”,IEEE

Antennas and wireless propagation letters, Vol. 14,

2015.

[3] JianhuiBao ,Qiulin Huang, Xinhuai Wang, and

Xiaowei Shi, “Compact Multiband Slot Antenna for WLAN/WiMAX Operations”, International Journal of

Antennas and Propagation Volume 2014, Article ID

806875.

[4] Poorwa Bhagat, Prof. Prashant Jain, “Triple Band Microstrip Patch Antenna with Dual U Slot for WLAN/WIMAX Applications” SSRG International

Journal of Electronics and Communication Engineering

(SSRG-IJECE) – volume1 issue7 Sep 2014.

[5] M.Z.M. Nor, S.K.A. Rahim, M.I. Sabran& F. Malek,

“Dual-band, parabolic, slotted ground plane-directive antenna for WLAN applications”Journal of

Electromagnetic Waves and Applications, 2013.

[6] N.Haider, D.Caratelli, and A.G.Yarovoy “Recent developments in Reconfigurable and Multiband antenna technology”, International Journal of

Antennas and Propagation vol.2013 ID 869170.

[7] A. Taksala Devapriya, Gulfa Rani and S. Robinson,

“Dual resonant Microstrip patch antenna using metamaterial planar structures for S band and C band applications”, DOI: 10.21917/ijct.2016.0211

[8] Mohamed A. Bassiuny, Ehab K. I. Hamad, Wael A.

Aly, and Mohamed Z. M. Hamdallah, “Dual-band Microstrip Antenna for WiMAX Applications Using Complementary Split Ring Resonators”, 2016, 33rd

NATIONAL RADIO SCIENCE

CONFERENCE (NRSC 201 6), Feb 22-25, 2016,

Aswan, Egypt.

[9] S.C. Basaran, U. Olgun and K. Sertel, “Multiband Monopole antenna with complementary split-ring resonators for WLAN and WiMAX applications”,

Electronics Letters, Vol. 49 No. 10., 9th May 2013.

[10] Rajesh Saha, Santanu Maity, “Design of Dual Band Patch Antenna by Loading Metamaterial Structure on Rectangular patch”,International Journal of Wired and

Wireless Communications Vol.3, Issue 2, 2015.

design of dual band slotted microstrip patch …slotted frequency reconfigurable microstrip patch...

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