Simulation of 6 Elements Aperture Coupled Feed Planar Array Rectangular Microstrip Patch Antenna for CPE WiMAX Application at 3.

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1 Simulation of 6 Elements Apetue Coupled Feed Plana Aay Retangula Miostip Path Antenna fo CPE WiMAX Appliation at 3.3 GHz Yusnita Rahayu Depatment of Eletial Engineeing, Univesity of Riau Pekanbau, Indonesia vannebula21@yahoo.om Rezki Ananda Gusma Depatment of Eletial Engineeing, Univesity of Riau Pekanbau, Indonesia toa_gusma@yahoo.om Abstat In this pape, Simulation of the 6 Elements Apetue Coupled Feed Plana Aay is designed fo CPE WiMAX Appliation. This Antenna uses Apetue Coupled feed to impove bandwidth. The Poposed antenna is ompaed to simila design of antenna with Miostip Line feed, to justify that the poposed antenna podues boade bandwidth. Both of Antennas ae designed and simulated by using HFSS simulation softwae and opeated in WiMAX fequeny ange of 3.3 GHz. The 6 Elements Apetue Coupled Feed antenna gives an impedane bandwidth of 1.53 %, this is boade than the 6 Elements Miostip Line Feed Antenna whih is only has impedane bandwidth of 6.23 %. The maximum gain is obtained dbi at 3.4 GHz. Details of antenna design ae given and simulation esults ae disussed. Keywods CPE WiMAX, apetue oupled, bandwidth, gain. I. INTRODUCTION Woldwide Inteopeability fo Miowave Aess (WiMAX) is a Boadband Wieless Aess (BWA) tehnology whih has high data tansfe speed (up to 7 Mbps) and lage aess ange (up to 5 km) [1]. In aoding to egulation, Ministy of Communiation and Infomatis of Indonesia, No. 5 /KEP/M.KOMINFO/1/29 stated that the fequeny band used fo WiMAX tehnology is GHz [2]. To aess the WiMAX netwok, it is equied a Custome Pemise Equipment (CPE) in the subsibe station. Cuently, the existing size of CPE is 2 x 2 m. Miostip antenna has numeous advantages that it has small size, low fabiation ost, light weight and it an be easily installed on the CPE. Miostip antenna has vey naow bandwidth. The bandwidth an be impoved by Apetue Coupled feeding tehnique [3]. Single laye miostip line feed elements ae typially limited to bandwidth of 2-5%. But apetue oupled antenna povides up to 1-15% of bandwidth with single laye [4]. Fig. 1 shows an oveview of a miostip path antenna design with apetue oupled tehnique. In this figue two substates; one fo feed line and anothe fo path ae fomed. A slot is fomed at ente of gound and feed line is below the seond substate as shown in Fig. 1. These types of antennas ae moe popula, beause of the pathes and slots an be any shape and this gives the impovement in the pefomane of miostip path antennas. Fig. 1. Tehnique of Apetue Coupled Feed In [5], this pape pesents design of etangula miostip antenna by using apetue oupled feeding tehnique. The antenna opeates at two bands Bandwidth-2 (BW2) and Bandwidth-3 (BW3). The impedane bandwidths of BW2 and BW3 ae found to be 23.87% and 21.68%, espetively. The simila study was onduted by [6], whee in antenna onfiguation onsisted of 16 aay elements. They used apetue oupled feeding fo exiting aay elements and obtained nealy 11% of impedane bandwidth. This study [7] pesents apetue oupled staked path antenna using ai gap vaiation, the measued etun loss exhibit an impedane bandwidth of 35% in the fequeny ange of 2.9 GHz to 6. GHz. This pape desibes the design and simulation of etangula miostip path antenna aay fo the CPE WiMAX whih opeates at 3.3 GHz band by using apetue oupled feeding tehnique. The simulation is developed in Ansoft HFSS with the speifiations shown in the Table I below. TABLE I ARRAY ANTENNA SPECIFICATION Featues Cente fequeny (λ ) Aay Antenna Configuation Miostip Radiato used Antenna Gain Requied Values 3.35 GHz 6 Elements Plana Aay Retangula Path 6 db Antenna impedane BW 1 % 451

2 Compaison between the poposed antenna with simila design using Miostip Line feed is done to justify that this antenna bandwidth is boade than that one. II. DESIGN OVERVIEW In this pape, two antennas design ae simulated. One antenna uses apetue oupled feed and the othe one uses miostip line feed. Bandwidth of both antennas will be ompaed and analyzed. Mateials used fo antenna design ae shown in the Table II and seveal steps used in the antenna design as following: TABLE II MATERIALS OF ANTENNA DESIGN Paametes Input Impedane (Z ) Path Mateials Conneto SMA 5 Ω Coope Substate FR4 (Epoxy); ε =4.4 Gound plane Radiation Box A. Design of Path Dimensions Coope In this design, the path used is etangula fom that has a width and a length. Equation (1)-(5) is used to alulate the width and length of path [7]. 1) Calulation of the Path Width (W): W 2 f ( 1 2 2) Calulation of Path Length (L): To detemine the length of the path (L) equied paamete ΔL whih is the length of L that due to the finging effet. The inease of length L (ΔL) is given by: ΔL, 412h W, 3, 264 h W, 258,8 h Ai (1) (2) Whee L eff is the effetive length of the path an be given by: L L eff 2ΔL (5) Fom that equation, the width and length of path obtained ae mm and 21 mm, espetively. Size optimization has been done fo path length of antenna design with miostip line feed. The optimized length is 21.5 mm instead of 21 mm. The optimized is pefomed to get ente fequeny fixed at 3.35 GHz. B. Design of Feed Netwok Feed netwok is the feed line onfiguation of aay antenna. Feed netwok onsists of 5 Ω feed line and T- juntion. The T-juntion used has an impedane of 7.71 Ω and 86.6 Ω. 1) Calulation of the 5 Ω feed line Width (W f ): Feed line used in this design has an impedane of 5 Ω. The width of the 5 Ω feed line is given by equation (6) and (7) [8]: 2 6 B = Z 2h 1,61 W B 1 ln 2B 1 ln B 1,39 2 Fom the equation, the feed line width is obtained 3.6 mm. 2) Calulation of the T-Juntion: This pape uses the T- juntion as a powe divide [1]. T-juntion used has an impedane of 7.71 Ω and 86.6 Ω. The width of 7.71 Ω is given by equation (6) and (7). Fom the equation, the feed line is 1.6 mm. To alulate the length of the feed line of 7.71 Ω is alulated by the equation (8) to (1): o 4 ef f (6) (7) l (8) Whee ε eff is an effetive dieleti onstant alulated by the equation: ε is the effetive dieleti onstant is given by: h 112 W Thus the path length (L) is given by: L eff 2 f (3) (4) W 2h 1,61 B 1 ln 2 B 1 ln B 1,39 h 2 ε = W / h (9) (1) Fom the alulation, the length of the 7.71 Ω feed is obtained mm. In addition, T-Juntion 86.6 Ω is also used fo 3 banhing points. By using the same equations, the 452

3 width and length of 86.6 Ω ae obtained.98 mm and mm, espetively. C. Design of Apetue Slot Design of apetue slot is only used by antenna using apetue oupled feed. The width and length of the slot apetue detemined by using Equation (11) and (12) [9]. La,2,289,55 18 mm (11) a W,1 L,118 1,8 mm a (12) Fom the alulation, the slot width (W a ) and length (L a ) ae 1.8 mm and 18 mm. Size optimization has been done fo slot apetue length. The optimized length is 2.3 mm instead of 18 mm. The optimized is pefomed to get ente fequeny fixed at 3.35 GHz. Table III is antenna dimensions afte optimization. TABLE III ANTENNA DIMENSIONS AFTER OPTIMIZATION substate-1. The netwok feed onsists the 5 Ω feed line and T-Juntion. The 5 Ω feed line has the length of 2 mm afte it was optimized. The apetue slots ae plae on the top sufae, as shown in Fig. 2 (b), whih is the gound plane of the substate-2 exatly at the below ente of the adiating elements. The apetue slot has 2.3 mm x 1.8 mm size afte it was optimized. The substate-2 is plaed below the substate-1 that foms apetue oupled feed. The adiating elements ae plaed on the top sufae of substate-1 shown in Fig. 2 (a) enegizes though oupling slots. The SMA onneto is used at the tip of 5 Ω feed line fo feeding the miowave powe ,25 17,52 27,25 Dimensions Substat FR- 4 (epoxy) Path Gound Plane 5 Ω Feed Line T-Juntion (86.6 Ω) T-Juntion (7.71 Ω) Apetue Slot Values Paametes Apetue Coupled Feed Miostip Line Feed Length (L s ) mm mm Width (W s ) 96.2 mm 96.2 mm Length (L p ) 21 mm 21.5 mm Width (W p ) mm mm Length (l g ) mm mm Width (w g ) 96.2 mm 96.2 mm Length (L 5 ) 2 mm 5 mm Width (W 5 ) 3.6 mm 3.6 mm Length ( L 86.6 ) mm mm Width ( W 86.6 ).98 mm.98 mm Length ( L 7.71 ) mm mm Width ( W 7.71 ) 1.6 mm 1.6 mm Length (L a ) 2.3 mm - Width (W a ) 1.8 mm - 18, , , (a) Top view of substate-1 27,62 1,8 42,98 1,8 42,98 1,8 21,59 (b) Top view of substate ,472 2, ,3 15,472 III. DESCRIPTION OF ANTENNA GEOMETRY Fig. 2 shows geomety of 6 Elements Apetue Coupled Feed Plana Aay. This antenna is designed using two FR-4 (epoxy) substates having 1.6 mm thikness (h) and 4.4 dieleti onstant (ε ). The gap between the substate-1 and substate-2 is 3 mm. Radiating elements (path) ae ethed on the top sufae of the substate-1. Usually in aay onfiguation, spaing between two adiating elements is kept at a distane λ o /2. The netwok feed is ethed below the substate-2 as shown in Fig. 2 () having thikness (h) and dieleti onstant (ε ) as that of 25, ,15 12, ,3 3,72 24,9 17,635 () Bottom view of substate-2 Fig. 2. Geomety of 6 Elements Apetue Coupled Feed Plana Aay 12,57 453

4 Fig. 3 shows geomety of 6 Elements Miostip Line Feed Plana Aay. This antenna only designed using one substate. The adiating elements and netwok feed ae ethed on the top sufae of the substate. The gound plane is plae below of the substate. The spaing between two adiating elements and netwok feed ae used same with antenna using apetue oupled feed. But the 5 Ω feed line has the length of 5 mm and then length of adiating element is 21.5 mm afte it was optimized. VSWR at 3.3 GHz, 3.35 GHz and 3.4 GHz ae 1.245, and , espetively. The vaiation of etun loss vesus fequeny of 6 Elements Miostip Line Feed Plana Aay is shown in Fig. 6 fo ompaison. Value of the VSWR at 3.3 GHz, 3.35 GHz and 3.4 GHz ae 1.343, 1.515, and , espetively. w3 w5 w6 wp l3 l7 lp w1 l1 l4 l9 l8 l5 w4 l6 d1 ws Fig. 5. VSWR gaph of 6 Elements Apetue Coupled Feed Plana Aay w2 l2 d2 Fig. 3. Geomety of 6 Elements Miostip Line Feed Plana Aay ls IV. SIMULATION RESULT The antenna design is modeled by using Ansoft HFSS softwae. The solution setup is 3.35 GHz and fequeny sweep of 3.1 until 3.6 GHz with step size 1 MHz and the setting boundaies is Pef E and Radiation. Fig. 4 shows the omplete antenna validation. Fig. 6. Geomety of 6 Elements Miostip Line Feed Plana Aay Fom Fig. 5 and 6, the impedane bandwidth is alulated using the following fomula [11]: f2 f1 Bandwidth 1 % (13) f Fig. 4. Validation Chek The vaiation of etun loss vesus fequeny of 6 Elements Apetue Coupled Feed Plana Aay Retangula Miostip Path Antenna is shown in Fig. 5. In this gaph shows what the antenna opeates at GHz fequeny. Value of the Whee, f 2 and f 1 ae highe and lowe ut-off fequeny of the band espetively, when its etun loss eahes db (VSWR 1.9) and f is the ente fequeny of this band. Compaison of bandwidth between antenna using apetue oupled feed with antenna using miostip line feed is given in Table IV. 454

5 TABLE IV COMPARISON OF ANTENNA BANDWIDTH Antenna Lowe Highe Cente Bandwidth MHz % 6 Elements Miostip Line Feed Plana Aay Elements Apetue Coupled Feed Plana Aay In Table IV shows the 6 Elements Miostip Line Feed Plana Aay having an impedane bandwidth of 28 MHz (6.23 %). And then the 6 Elements Apetue Coupled Feed Plana Aay Retangula Miostip Path Antenna gives boade impedane bandwidth (1.53%) when ompaed to antenna using miostip line feed. The 6 Elements Apetue Coupled Feed Plana Aay ahieves bandwidth of 1% whih is usually bandwidth obtained single element antenna using apetue oupled feed. Fig. 7 shows the gain of eah antenna. In Fig. 7 (a), gain of 6 Elements Apetue Coupled Feed Plana Aay Retangula Miostip Path Antenna is dbi. This gain has ahieved the equied speifiation ( 6 dbi). (a) (b) m1 XY Plot Theta [deg] 6 Elements Apetue Coupled Feed Plana Aay Retangula Miostip Path Antenna m1 Name X Y m Name X Y m XY Plot 1 6 Elements Miostip Line Feed Plana Aay Retangula Miostip Path Antenna Fig. 7. Gain of Antennas Cuve Info This antenna gain is highe when ompae to the 6 Elements Miostip Line Feed Antenna whih is only has gain of dbi as shown in Fig. 7 (b). Apetue oupled antenna is able to deease sufae wave. This impoves the gain. 27,27 Setup1 : LastAdaptive Feq='3.35GHz' Phi='31deg' Elemen Tunggal (AC) Cuve Info Impoted Feq='3.4GHz' Phi='9deg' Theta [deg] ANSOFT ANSOFT V. CONCLUSION Simulation 6 Elements Apetue Coupled Feed Plana Aay opeating at 3.3 to 3.4 GHz ompleted. This miostip antenna has an impedane bandwidth of MHz (1.53%). This antenna has boade bandwidth than antenna using miostip line feed (6.23%). The 6 elements apetue oupled feed antenna has a gain of dbi. This antenna has ompat in size of about 15 x 1 m and suitable on the CPE WiMAX devie. V. REFERENCE [1] Gauav Jindal & Vinay Gove, Voie and Video ove the WiMAX, Intenational Jounal fo Compute Appliation and Reseah (IJCAR, ISSN: ), Vol. Speial Issue 1, pp , Febuay 213. [2] Ministe of Communiation and Infomation, 29. Deision of the Ministe of Communiation and Infomation Numbe: 5/KEP/M.KOMINFO/1/29 About Detemination of Radio Band Bloks and Wieless Boadband Sevie Zones On the 3.3 GHz Radio Band fo Existing Radio Band Uses fo Wieless Boadband Sevie Requiement. [Online]. Available: Http :// publikasi.kominfo.go.id/handle/ /61. [3] Kau Manpeet, Kau Amanpeet & Khanna Rajesh, A Miostip Path Antenna with Apetue Couple Tehnique At 5.8 GHz & 2 GHz, Intenational Jounal of Moden Engineeing Reseah (IJMER), Vol. 3, Issue. 1, PP Jan-Feb 213. [4] Chakaboty S, Gupta B & Podda D R, Development of Closed fom design fomulae fo apetue oupled miostip antenna, JSi Ind Res (India), 64 (25) 482. [5] B. Suyakanth & S. N. Mulgi, Design and Development of Apetue Coupled Retangula Miostip Antenna fo Dual Band Opeation Intenational Jounal of Advaned Reseah in Eletial, Eletonis and Instumentation Engineeing (IJAREEIE, ISSN: ), Vol. 2, PP , Agustus 213. [6] Nwalozie G.C, Okoogu V.N, Okafo A.C & Oweh V.E, Simulation Implementation of Miostip Antenna Aay fo 1.8 GHz Band With 1 db Gain, Intenational Jounal of Emeging Tehnology and Advaned Engineeing (IJETAE), Vol. 2, Issue 12, Deembe 212. [7] Rajesh Kuma Vishwakama & Sanjay Tiwai, Apetue Coupled Staked Path Antenna fo Dual Band, Intenational Jounal of Eletonis and Compute Siene Engineeing (IJECSE, ISSN: ), Vol. 1, No. 3, PP , 212. [8] James J. R., Hall P. S., eds. Handbook of Miostip Antenas. Vol. I and II. Pete Peginus. IEEE [9] Rambe, Ali Hanafi, Design of 4 Elements Plana Aay Retangula Miostip Path Antenna fo WiMAX CPE Appliations, Gaduate Thesis, Univesity of Indonesia, Indonesia: 28. [1] David M. Poza, Miowave Engineeing, John Willey and Sons, [11] Mulgi S. N, Pushpanjali G. M, Konda R. B, Satnoo S. K & Hunagund P. V, Boadband Apetue Coupled Equilateal Tiangula Miostip Aay Antenna, Indian Jounal of Radio & Spae Physis, Vol. 38, PP , Juni