miniaturized inset-fed patch antenna for wireless · for the design and analysis of the microstrip...

MINIATURIZED INSET-FEDRECTANGULAR MICROSTRIP

PATCH ANTENNA FOR WIRELESSLAN APPLICATIONS

Venkateswaran S1, Rajasekar.J2,Department of Electronics and Communication Engineering,

Meenakshi Sundararajan Engineering College,Chennai, India.

[email protected],[email protected]

May 27, 2018

Abstract

The objective of this paper is to miniaturize an inset-fed rectangular microstrip patch antenna which operates at2.4GHz. Defected ground structures (DGS) are incorpo-rated on the ground plane and the slots are employed onthe patch to shift the resonant frequency from 5.2GHz to2.4GHz by disturbing the current distribution of antenna.Ansoft HFSS tool is adopted in the design and analysis ofthe performance of antenna. The peak gain of the proposedantenna is found to be 0.3145, is capable of radiating sig-nals with an efficiency of 0.7751 with the peak directivityof 0.4057. The return loss, current distribution, 3D radi-ation pattern has been estimated. The S11 parameter ofthe antenna is -21.1 dB at 2.4 GHz. FR4 Epoxy substratewith a dielectric constant of 4.3 is used in the fabrication ofantenna. The measured result shows that the antenna hasS11 parameter of -33.7 dB at 2.38GHz with a bandwidth of

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International Journal of Pure and Applied MathematicsVolume 118 No. 24 2018ISSN: 1314-3395 (on-line version)url: http://www.acadpubl.eu/hub/Special Issue http://www.acadpubl.eu/hub/

300MHz. The overall size of the antenna is about 27.32 *22.96.

Key Words:Miniaturize, Inset-fed, FR4 Epoxy, DGS,Slots.

1 Introduction

An antenna can be defined as the means for radiating or receivingradio waves. For wireless applications, the antenna is one of themost major components. A concrete design of the antenna relaxesthe requirements of the system and improves the performance of thesystem. The antenna domain is strenuous over the past 65 yearsand the antenna technology has been a vital partner of the revo-lution in communications. There are many issues and challengesthat are faced for the demand in the performance of the system,however the major advances which occurred during that period arein common use today [1]. The microstrip antennas are simple, low-cost, low profile, amenable to planar and nonplanar surfaces. Theyare mechanically robust when mounted on rigid surfaces and fabri-cation using modern printed-circuit technology is quite simple [2].For the design and analysis of the Microstrip Patch Antenna, HighFrequency Structure Simulator (HFSS) software is used in this pa-per as it provides accurate results. For the simulations of highfrequency it is a special tool.

2 INSET FEEDING

To radiate, a feed line by direct or indirect contact is used to ex-cite. Many different techniques of feeding can be employed but themost widely adopted techniques are inset feed, coaxial probe feed,microstrip line, aperture coupling and proximity coupling [3]. Wehave designed an inset-fed microstrip patch antenna in this paper.Initially, patch antennas were fed at the end. But this inset-fedgives high impedance at the input; hence the feed is modified asshown in Fig.1. The input impedance (Z=V/I) can be reduced ifthe patch was fed closer to the center, the currents are low at theends of a half wave patch and the magnitude of current increasestowards the center. This can be achieved by using the inset fed.

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International Journal of Pure and Applied Mathematics Special Issue

A microstrip inset feed patch antenna with miniaturized size is towork as both receiver and transmitter at 2.4GHz is proposed in thispaper.

Figure 1 Layout of an Inset-Fed Patch

The current by nature has the distribution sinusoidally, movingat a distance Yo from the end towards the center increases thecurrent by cos(R/L) [3].

3 EFFECT OF DGS AND SLOTS

Defected Ground Structure is one of the methods which can beadopted to reduce the size of a patch antenna. In this method asimple or complicated shapes are etched on the ground plane. By

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varying the various dimensions of the etched shape, desired reso-nant frequency can be achieved [4]. Fig.2 shows the DGS structurallayout which is incorporated in the copper ground plane. The DGScomposes from 6 rings which are concentric shaped with a slot inrectangular shape. By varying the size of the rings in concentricshape or the size of slots in rectangular shape, the shift in reso-nant frequency can be achieved. A contemporary etched shape isadopted as a defected ground structure (DGS), with the aim toreduce the size of proposed microstrip antenna which initially res-onated at 5.2 GHz. After the use of DGS method the antennaresonates at 2.4GHz which can be adopted for Wireless LAN ap-plications.

Figure 2 Layout of the Proposed DGS

The bandwidth and gain can be improved by adopting slotson the antenna patch element. With the usage of the slots on theantenna patch, causes sinuous of current paths on the excited patchsurface and it results in downshifting of the resonant frequency,which results to the antenna size reduction [5] when compared toan ordinary microstrip patch antenna. Performance of the patchantenna can be enhanced when the patch edge width cut is morethan its length [6]. By employing slots on the patch element anE-shaped patch is constructed by removing the edges of the patchin this paper.

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4 DESIGN CALCULATIONS

The following steps are followed to design the antenna [2]: Step 1:Calculation of Width of the patch (W):

Substituting C = 3x108 m/s, εr = 4.3 and fr = 5.2 GHz, W =0.01772 m = 17.72 mm.Step 2: To Calculate the Effective dielectric constant (εeff ):

Put εr = 4.3, W = 17.72 mm and h = 1.6 mm we get: (εreff ) =3.7931. Step 3: To Calculate the length extension (∆L):

Put (εreff ) = 3.7931, W = 17.72 mm and h = 1.6 mm, (∆L) =0.7288 mm. Step 4: To Calculate actual length of the patch (L):

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Substituting C=3x108 m/s, (εreff ) =3.7931, fr=5.2 GHz and (∆L)=0.7288mm we get: L=0.01336 m = 13.36 mm. Step 5: To CalculateGround plane dimensions (Wg and Lg):

Substituting L=13.36 mm, W = 17.72 mm, h = 1.6 mm we get:Wg =27.32 mm, Lg =22.96 mm. Step 6: Calculation of the Feedline dimensions (Wf and Lf ): Feed line dimensions are taken asfollows: Wf = 3 mm and Lf = 8 mm. Step 7: Determination ofinset depth and inset gap (Yo and g): Yo = (0.822 * L) / 2 = 5.4909mm and g = Wf / 10 = 0.3 mm.

TABLE I Design Parameters and its Dimensions

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5 HFSS SIMULATION RESULTS AND

IMPLEMENTATION RESULTS

Figure 3 Structure of Simulated Antenna

Figure 4 Current Distribution Pattern

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Figure 5 Radiation Pattern of proposed Antenna

Figure 6 Module of the proposed Miniaturized MPA

Fig.3 shows the three dimensional Structure of proposed An-tenna with E-shaped Patch and with the Defected Ground Struc-ture, where we have used split ring resonator at the ground plane.Fig.4 shows the current distribution pattern of the proposed an-tenna and it shows that it radiates more at the ends of the patch.Fig.5 shows the Radiation pattern of the proposed antenna which

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radiates at -7.28 dB on all the directions. The working model ofthe proposed system is shown in the fig.6.

Figure 7 Simulated and Measured S11 parameter of antenna

Fig.7 shows the simulated and measured S11 Parameter of theproposed antenna and it shows that the antenna has wider band-width and less than 0.25% of power is only transmitted back to thetransmitter. The antenna is fed through an SMA connector andthe result is measured using vector network analyser. A vector net-work analyser analyses the RF performance of devices at Radio andmicrowave frequencies. It characterizes in terms of S parameters [7].

6 CONCLUSION

The simulation and measured results of the miniaturized inset-fedrectangular microstrip patch antenna over an FR4 epoxy substratefor WLAN applications using HFSS Software have been investi-gated. A good impedance matching between the receiver and trans-mitter has been achieved by using the inset feed technique. Asseen from their simulation result, the designed rectangular patchantenna has higher efficiency of about 77.5%, wider bandwidth ofabout 300MHz, and compact in its size when compared to the ordi-nary rectangular patch antenna at 2.4GHz. The overall size of theantenna is about 27.32 * 22.96. The antenna has omni-directionalpattern and hence it is suitable for various mobile applications. Thegain of the antenna can be further improved by using the Array ofantennas.

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7 ACKNOWLEDGEMENT

The authors would like to acknowledge Mrs.N.Meenakshi, SeniorAssistant professor, Meenakshi Sundararajan Engineering Collegeand Mr.S.Dinesh Moorthy for supervising and providing the neces-sary support to implement the project successfully.

References

[1] Shaoqiu Xiao,Yan Zhang, Honglin Hu, Bailong Xiao andBing-Zhong Wang. Antenna System in Telecommunications.Telecommunication systems and technologies.

[2] A.Balanis, John Wiley Sons, New Jersey. Antenna theoryAnalysis and design. Fourth Edition, Constantine., 2016.

[3] B. Patil Rajendra D. Kanphade Vivek V. Ratnaparkhi. De-sign and Performance Analysis of Inset Feed Microstrip SquarePatch Antenna for 2.4GHz Wireless Applications by Santosh.IEEE sponsored 2nd international conference on electronicsand communication system (ICECS), 2015.

[4] R.Er-rebyiy, J.Zbitou, A.Tajmouati, M.Latrach, A.Errkik,L.El Abdellaoui. A New Design of a Miniature MicrostripPatch Antenna Using Defected Ground Structure DGS.

[5] Dr. R.K. Khola, Naveen Kumar Gupta. Design of MultibandMicrostrip Patch Antenna for Wireless 1 GHz to 5 GHz BandApplications with Microstrip Line Feeding Technique. Inter-national Journal of Computer Science and Mobile Computing,June- 2015.

[6] Charles U. Ndujiuba, Oluwafemi A. Ilesanmi, Oboyerulu E.Agboje. Effect of Edge-cut Dimensions on the Electrical Pa-rameters of an Inset-fed Rectangular Microstrip Patch An-tenna with Partial Ground. International Journal of Networksand Communications, 2017.

[7] Vector Network Analyser (VNA) - http://www.radio-electronics.com/info/t−and−m/rf-network-analyzer/vector-analyser-vna-tutorial.php.

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[8] Anjali K J, Suriyakala CD. A Highly Miniaturized Patch An-tenna. International Conference on circuits Power and Com-puting Technologies [ICCPCT], 2017.

[9] H. Nornikman, B. H. Ahmad, M. Z. A. Abd Aziz, A. R. Oth-man. Effect of Single Complimentary Split Ring ResonatorStructure on Microstrip Patch Antenna Design. IEEE Sym-posium on Wireless Technology and Applications (ISWTA),2012.

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miniaturized inset-fed patch antenna for wireless · for the design and analysis of the microstrip...

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