Deepak Sawle, Prof. Rajesh Nema / International Journal of Engineering Research andApplications (IJERA) ISSN: 2248-9622 www.ijera.comVol. 3, Issue 3, May-Jun 2013, pp.567-571567 | P a g eMicrostrip Patch Array Antenna Pattern Design With ActiveElementDeepak Sawle *, Prof. Rajesh Nema ***(Department Of Electronics and Communication , NIIST Bhopal ,India )**(Department Of Electronics and Communication , NIIST Bhopal ,India,)AbstractThis paper proposed design ofmicrostrip phased patch array antenna . Theproposed design array is combination of linearand colinear feed with active element . TheActive element pattern technique is applied foranalyzing microstrip array, which reducesanalysis problem and computation . The mutualcoupling effect is added in the results of theproposed design . The FR-4 substrate withDielectric constant 4.3 and loss tangent 0.019 isused for proposed design at resonant frequencyof 3 GHz. Radiation characteristics, gain andreturn loss of the planar array antenna issimulated using Zeland IE3D simulationsoftware . Operating frequency of theseantennas are 3 GHz, 3.5 GHz and 5.4 GHz , sothese design is suitable for S-band and C-bandapplication.Kyewords :- Microstrip patch , array antenna ,Mutual Coupling, IE3D .I . INTRODUCTIONThe Microstrip patch array antenna areperfect choice for S-band and L-band variousapplication due to following features, low profile,small size and conformability. But microstripantennas suffer from bandwidth limitations. Thebandwidth can be increased by adding lossyelements but it affects efficiency of the antenna. Sothe better method is to use array antenna. Thisdesign of microstrip array antenna is for Wimaxand WLAN applications. The microstrip patchantenna is design at resonant frequency of 3GHz,This designed added mutual coupling into accountof simulated results . With this active array patternthe simulation time will be reduced and calculationwill be easier . The spacing difference between twoelement is λ/4 for introducing mutual couplingbetween the elements .The common probe feeding isgiven to the centered active patch in my designbased on slot coupling . Ring shaped slot is on theradiating patch and two rectangular slots on groungplane . Due to many advantages such as low profile, light weight , low cost ,ease of fabricationmicrostrip are widely applied in communicationsystem . The simulated results of the proposeddesign achives a triple band 2.9 GHz to 3.2 GHz ,3.3 GHz to 3.6 GHz and 5 GHz – 5.6 Ghz (returnloss less than -10dB). At this frequency band it isalso useful in WiMAX aplications and third bandprovide applications for wilreless local area network( WLAN ) services such as IEEE 802.11a in theUSA (5.15 to 5.35 GHZ,5.7 to 5.825GHz ) andHIPERLAN/2 in Europe (5.15 to 5.35 GHZ , 5.47 to5.725GHz) .II.DESIGN METHODOLOGY ANDPARAMETERSTheoretical analysis and calculation of a singlemicrostrip patch is calculated with followingequations  :The first step is to find the width , W of the patch atthe resonant frequency using Equation 1 ;o rc 2w=2f ε +1 ………………………….. (1)Where εr is the relative permittivity of the substrate,c is the speed of the light in free space and fo is theresonant frequency .Length of the patch is calculated by Equation 2;o effcL=2f ε………………(2)Where , εeff is the effective dielectric constant of thesubstrate . To measure for the fringing effects , theactual length of the patch also includes thecorrection factor due to fringing effect . Actuallength is given by Equation 3 ;r eff-2ΔLcL=2f ε……………………(3)Correction factor can be found using the equation 4;effeffw(ε +0.3)( +0.264)hΔL=0.412hw(ε -0.258)( +0.8)h………(4)Where , h is the height of the substrate .εeff, effective dielectric constant used in equation 4 isgiven by Equation 5.1-2r reffε +1 ε -1 hε = + 1+122 2 w ………….(5)
Deepak Sawle, Prof. Rajesh Nema / International Journal of Engineering Research andApplications (IJERA) ISSN: 2248-9622 www.ijera.comVol. 3, Issue 3, May-Jun 2013, pp.567-571568 | P a g eGround patch of the geometry is design with thefollowing equation 6 ;Length of ground patch, Lg = 6h+L ………. (6.a)Width of ground patch, Wg = 6h+w ……… (6.b)The dimensions for designing a single microstrippatch are tabled below :Table 1. Antenna Design parametersAntenna parameters DimensionsResonant frequency fo 3GHzDielectric constant εr 4.3Height of Substrate (h) 1.5mmWidth (W) 30.72mmLength (L) 23.74mmEffective dielectric substrateεeff3.96Widht of ground patch Wg 32.74mmLength of ground patch Lg 39.72mmThe antenna array geometry is designed withspacing between center element and rest fourelements is λ /4 . The proposed geometry is withsingle patch and with four patches shown in fig. 1Fig.2.Geometry of proposed phased arrayantennaIII.SIMULATION AND RESULTSThe proposed geometry of microstripphased array antenna designed with IE3D andsimulation is perfomed . At the resonant frequencyof 3GHz the design is simulated in the frequencyrange of 1 to 6GHz. The proposed phased arrayantenna has scanned at angle of 80oand 90oin thearray .The radiation pattern is bidirectional.Thesimulated return losses versus frequency for thearray exhibits in fig.3.The returnlosses at threefrequency bands are -17.56dB at 3 GHz , -26.98dBat 3.5 GHz, and -23.9dB at 5.4GHz. The impedancebandwidth for these with returnlosses of theproposed array is about to 9.83% ,9.45% and 14.9%in three frequency bands which cover LTE(longterm evalution ) in 4G , WiMAX and WLANapplications . The total radiation efficiency is about100% in all three bands shown in fig.4 .The axialratio below 3db shwn in fig.5, and VSWR is nearabout 1 as shown on fig.6. The gain is achived17.56dBi at 3.5GHz and it is over 22dBi at 5.4 GHz.The gain versus frequency graph is shown infig.7.The directivity of the proposed phased arrayantenna is shown in figure 8 .The Impedancematching is shown in smith chart is shown in fig.9,its shows proper impedance matching at frequeFig.1. Geometry of proposed single patch array 3.5GHz and 5.4GHz. Figur.10 shows 3-D radiationpattern .Cartesian ploting of elevation angle versusgain of three frequencies is shown in
Deepak Sawle, Prof. Rajesh Nema / International Journal of Engineering Research andApplications (IJERA) ISSN: 2248-9622 www.ijera.comVol. 3, Issue 3, May-Jun 2013, pp.567-571569 | P a g efigure11.Azimuth Cartesian graph is shown infigure.12. The returnloss , bandwidth , and antennaefficiency gain and directivity are compared withprior works shown in [4-7]Fig.3 Return loss Vs FrequencygraphFig.6 VSWR of proposed array antennaFig.7 Gain Vs frequency of proposed arrayantennaFig.4 Antenna Efficiency of the proposed designFig.5. Axial Ratio of proposed array antennaFig.8 Directivity Vs frequency of proposedarray antenna
Deepak Sawle, Prof. Rajesh Nema / International Journal of Engineering Research andApplications (IJERA) ISSN: 2248-9622 www.ijera.comVol. 3, Issue 3, May-Jun 2013, pp.567-571570 | P a g eFig.9 Smith Chart of proposed array antennaFig.10. 3-D Ration Pattern at 5.4GHzFig11.a. Elevation Pattern Gain at 3GHzFig11.b. Elevation Pattern Gain at 3.5GHzFig11.c. Elevation Pattern Gain at 5.4GHzFig.12 Azimuth Pattern Gain at 3GHz, 3.5GHzand 5.4GHz
Deepak Sawle, Prof. Rajesh Nema / International Journal of Engineering Research andApplications (IJERA) ISSN: 2248-9622 www.ijera.comVol. 3, Issue 3, May-Jun 2013, pp.567-571571 | P a g eCONCLUSIONThe novel design method is proposed inthis paper. This design can be implement for LTE(4G),WiMAX and WLAN application with mutualcoupling . Consequently the feeding network canbe greatly simplified and it can also beimplemented in large array with active arrays andby using the mutual coupling effect of the activearray.REFERENCES M.A. Soliman, T.E. Taha, W.Swelam, andGomaa, “3.5/5Ghz Dual Bnad 8×8Adaptive Array Antenna ”, Progress InElectromagnetics Research, Vol.34,pp. 85-98 , ,2013. Balanis, C.A., Antenna Theory Analysisand Design, 3rdedition , John Willy &Sons, 2005. Bojana Zivanovic, Thomas M. Weller ,and Carlos Coatas “Series-FedMicrostrip Antenna Array and TheirApplications to Omni-Directional Antenna”, IEEE Trans. AntennaPropag.,Vol.60,No.10. pp.4954-4959,October2012. Yue Li,Zhijun Zhang and Zhenghe Feng“A Sequential-phase feed using acircularly polarized shorted loop structure” IEEE Trans. AntennaPropag.,Vol.61,No.3 pp.1443-1447,March 2013 Bojana Zivanovic ,Thomas M.Weller, andCarlos Costas “Series-Fed MicrostripAntenna Arrays and Their Application toOmni-Directional Antennas”, IEEE Trans.AntennaPropag., Vol.60,No.10, pp.4954-4959,October 2012. K.P.Wei, Z.J.Zhang, and Z.H.Feng,”Designof dual band omnidirectionalplanar Microstrip Antenaa Array”,Progress In Electromagnetics Research,Vol.126,pp.101-120,2012. Yifei Zhang, Jian Bai, Shouyuan Shi, andDennis W. Prather,” Ka Band PhasedArray Antenna” IEEE Antenna & Prop.Symp., Chicago, IL July 2012.