IJEE Vlume-6 Number-1 Jan -June 2014 pp. 51-55 (ISSN: 0973-7383) Dual Band Micrstrip Patch Antenna fr Shrt Range Wireless Cmmunicatins S.Princy 1,A.C.Shagar 2 1 P.G Student, M.E Cmmunicatin Systems, Sethu Institute f Technlgy, Virudhunagar, India 2 Prfessr, Department f Electrnics and Cmm. Engg, Sethu Institute f Technlgy, Virudhunagar, India princy.sparks@gmail.cm, sagar_research@yah.cm Abstract: This paper describes the design and develpment f a simple patch antenna fr dual band peratins. The dualband peratin is btained by embedding a rectangular shaped slt in the radiating patch. The dielectric material used is FR4 substrate with the dielectric cnstant f 4.4 having thickness h =1 mm and a micrstrip line feeding methd is used. The entire size f the antenna is nly 13.47x17.52x1mm 3.The simulatin was perfrmed using Advanced Design System (ADS) sftware.this antenna is perating in IEEE 802.11a frequency range (5.2/5.8GHz). Furthermre, the prpsed antenna has a lw prfile, making it suitable fr wireless handheld devices and thus suitable fr shrt range wireless cmmunicatins. Keywrds: Dual band, IEEE 802.11a WLAN, Rectangular Slt, Micrstrip Patch Antenna. I.INTRODUCTION With the rapid develpment f wireless cmmunicatin systems, multiband antenna has been playing a vital rle fr wireless service requirements, eliminating the need fr separate antennas fr each applicatin. The wireless lcal area netwrk (WLAN) is ne f the mst ppular netwrks fr accessing the internet. WLAN has been widely recgnized as a viable, csteffective, and highspeed data cnnectivity slutin, enabling user mbility.in WLAN applicatins, mst attentin has been fcused n the requirement f prviding multiband peratins, such as cvering 2.4, 5.2, and 5.8 GHz bands fr the IEEE 802.11 b/astandards. Micrstrip patch antenna is preferred fr WLAN applicatins due t its lw prfile, lw weight, lw cst and small size. A simple methd used in WLAN antennas t cver the three bands is t use ne mnple fr the lwer band and anther mnple r a branch structure fr the tw higher bands [1, 2]. Hwever, due t the required length f mnple fr resnating in the lwer band, this methd leads t a relatively large antenna size. In [3], a pair f symmetrical hrizntal strips embedded in a slt n the grund plane was used t excite a dualband resnance. The slt ccupied a large area f abut 30 x14 mm 2. In [4], a direct-fed planar inverted antenna (PIFA) cmbined with a parasitic element was prpsed fr WLAN applicatins. The PIFA resnated in the fundamental mde at 2.4 GHz and the secnd-rder mde at 5.2 GHz. The parasitic element with ne end shrted t grund was used t generate the 5.8GHz band. Althugh the height had been reduced cmpared with ther PIFA antennas, the antenna was rather high prfile and still ccupied a larger vlume than a planar antenna due t the PIFA structure. Different techniques fr WLAN dualband designs are reprted in [1-7]. Hwever, these micrstrip antennas are nt specifically designed fr WLAN802.11a dual band. In [8], Deshmukh presented a bandwidth enhancement methd f micrstrip antenna using quarterwavelength resnant slts. Hwever, at the lwer frequencies, the higher crssplarizatin level is bserved. In [9], a cmpact dualband rectangular micrstrip antenna (RMSA) was realized by tw different singlesltted singleband rectangular micrstrip antennas with sltted grund plane. Hwever, the limitatin fund related t the packaging f the antenna is due t the presence f the slt in the grund plane. In [11], dual band mnple antenna was analyzed fr WLAN/WiMAX applicatins. Basic designand descriptin abut micrstrip antenna was reprted in [12 16].Cmpact and bradband design methds f lwprfile micrstrip antennas have been discussed in [17]. In this paper, the design f a dualband micrstrip antenna fr WLAN IEEE 802.11a band applicatin is realized by embedding a singlerectangular shaped slt in the radiating patch. The prpsed antenna cvers the 5.2/5.8 GHz WLAN 802.11a peratingband.the prpsed cnfiguratin was simulated using Advanced Design System (ADS). II.ANTENNA DESIGN The cnfiguratin f the prpsed antenna is shwn in Fig. 1. The rectangular patch is etched n a lw cst FR4 substrate with a dielectric cnstant f 4.4 and thickness f 1 mm. A 50 micr strip line with width (W f ) f 1.48 mm and length f 5.47mm is used fr feeding the antenna. By this cnfiguratin we can btain resnance at 5.2 GHz. Next a rectangular slt is embedded symmetrically n the rectangular patch fr dual band peratins. The dimensin f the slt is 5.8 x 0.3 mm 2. Due t the presence f the slt, a new resnant mde at 5.8 GHz can be easily exciteds as t btain the desired dualband peratin. The entire size f the antenna is nly 13.47x17.52x1mm 3.The parameters were adjusted t btain tw wide bandwidths suitable fr 5.2/5.8 GHz WLAN peratins. In rder t have the desired resnance at mre than ne frequency generally we can g fr multi band techniques. One f the efficient methds f achieving multi band peratin is cutting slts in the patch. The length and psitin f the slts can be changed t btain the micrstrip patch antennas resnating at mre than ne frequency. In this way we can have the dual r triple band antenna peratins.
L p W f W s L s W p X 0 Fig.1. Structure f the prpsed antenna S, inthe designf a dual band antenna, first the parameter value fr a single band peratincan be calculatedusing design equatins and then a slt cut f apprpriate length at apprpriate psitin bemade t btain dual band peratin. Accrdingly after getting the desired simulated results fr 5.2GHz frequency, the length f a slt made in the patch is adjusted t get it resnated at 5.8GHz frequency t. The ptimized values f the antenna dimensins are summarized in Tab. 1.The ptimized values f the slt cut are given in Tab. 2. The structure f the desired single band and dual band antennas are shwn in Fig. 2 and Fig. 3. Design equatins The dimensins f the patch alng its length have nw been extended n each end by a distance L, which is given by empirical equatins as fllws: Fig.2. Design f single band rectangular patch antenna L=0.412h ( + 0.3) (W/h + 0.264)/ (( - 0.258) (W/h + 0.8)) (1) The effective length f the patch L eff nw becmes: L =L p +2L (2) eff Fr a given resnance frequency f, the effective length is given by as: L p =c/ (2f ( ) (3) Fr a rectangular Micr strip patch antenna, the resnance frequency fr any TM mde is given as: f = c/(2( )[(m/l) 2 +(n/w) 2 ] 1/2 (4) Where, m and n are mdes alng L and W respectively. Fr efficient radiatin, the width W is given as: W p =c/ (2f (( r +1)/2)) (5) Table 1: Antenna dimensins Parameters Calculated value (mm) Patch width, W p 17.52 Patch length, L p 13.47 Fig.3. Design f dual band rectangular patch antenna Table 2: Slt dimensins Parameters Calculated value (mm) Slt width, W s 0.3 Slt length, L s 5.8 III.RESULTS AND DISCUSSION Simulatin f the Single Band Rectangular Patch Antenna The rectangular patch is etched n a lwcst FR4 substrate with a dielectric cnstant f 4.4 and thickness f 1 mm.a 50 micrstrip line with width f 1.48 mm and length f 5.47mm is used fr feeding the antenna. With this cnfiguratin, the simulatin was perfrmed and simulated return lssf the antenna is shwn in Fig. 4.
Return lss is the pwer f the reflected signal in a transmissin line. It is given in db. RL db = 20 lg10 Frm the figure 4,it is fund that the antenna resnates at 5.2 GHz and the crrespnding return lss is -12.778 db. Nw, the entire sizef the antenna is nly 13.47x17.52x1mm 3. Frm this Fig.5., it is bserved that the antenna resnates at 5.2 and 5.8 GHz. It is als fund that the impedance matching fr the first peratin is imprved. This is well knwn frm the change f return lss frm -12.77 db t - 14 db. Als -10 db impedance bandwidth is well fr 5.8 GHz peratin i.e. its value is fund t be -16.8 db. Current distributins In rder t clearly see the behavir f the prpsed antenna that creates dual band peratins in a cnventinal micrstrip antenna, the simulated current distributins at the perating frequencies f 5.2 GHz and 5.8 GHz were investigated by ADS simulatin sftware package, as the results illustrated in Fig. 6 and Fig.7. Fig.4. Return Lss Vs. Frequency Simulatin f the Dual Band Rectangular Patch Antenna Fig.6. Current distributin f dual band rectangular patch antenna (5.2GHz) In rder t explre the dual band peratins, a rectangular slt is embedded symmetrically n the rectangular patch. The dimensin f the slt is 5.8 x 0.3 mm 2. Due t the presence f the slt, a new resnant mde at 5.8 GHz is easily excited. The length and psitin f slt was adjusted t btain tw wide bandwidths suitable fr 5.2/5.8 GHz WLAN peratins. With this cnfiguratin, the antenna simulatin was again perfrmed and the simulated return lss f the antenna is shwn in Fig. 5. Fig.7. Current distributin f dual band rectangular patch antenna (5.8GHz) Frm these figures, it is well knwn that antenna resnates at the tw perating frequencies 5.2/5.8 GHz, which is indicated by the strng current distributins (Red arrws).the crrespnding antenna parameters are als shwn (Figure 8). Fig.5. Return Lss Vs. Frequency
5.8 GHz 5.2 GHz Fig.9. 3D Radiatin Patterns These radiatin patterns cnfirm that the radiatin f the prpsed antenna is well abve the radiating patch fr the dual band peratins. IV CONCLUSION A micrstrip patch antenna fr dual band peratins was designed and simulated. A dual band peratinhas been achieved by etching a single rectangular slt n the radiating plate. The resultant antenna was fund t perate in IEEE 802.11a frequency range (5.2/5.8GHz). The entire size f the antenna is nly 13.47x17.52x1mm 3 and it will be useful fr shrt range wireless applicatins. 5.8 GHz Fig.8. Simulated Antenna Parameters Radiatin patterns Radiatin pattern defines the variatin f the pwer radiated by an antenna. Fr the prpsed dual band antenna the 3D radiatin pattern is shwn belw (Figure 9). REFERENCES [1] T. N. Chang and J. J. Jiang, Meandered T-shaped mnple antenna, IEEE Trans. Antennas Prpag., vl. 57, n. 12, pp. 3976 3978, Dec.2009. [2] Q. X. Chu and L. H. Ye, Design f cmpact dualwideband antenna with assembled mnples, IEEE Trans. Antennas Prpag., vl. 58,n. 12, pp. 4063 4066, Dec. 2010. [3] D. Lin, Y. L. Zhen, Y. J. Xie, L. N. Ga, and J. Fan, A cmpact micrstrip slt triple-band antenna fr WLAN/WiMAX applicatins, IEEE Antennas Wireless Prpag. Lett., vl. 9, pp. 1178 1181, 2010. 5.2 GHz [4] H. Y. Wang and M. Zheng, An internal triple-band WLAN antenna, IEEE Antennas Wireless Prpag. Lett., vl. 10, pp. 569 572, 2011. [5] L. Li, S.W. Cheung, and T. I. Yuk, Dual band antenna with cmpact radiatr fr 2.4/5.2/5.8 GHz WLAN applicatins, IEEE Trans. AntennasPrpag., vl. 60, n. 12, pp. 5924 5931, Dec. 2012.
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