Design of Microstrip Antenna for Wireless Local Area Network

Transcription

1 Available Online at Intenational Jounal of Compute Science and Mobile Computing A Monthly Jounal of Compute Science and Infomation Technology IJCSMC, Vol. 4, Issue. 4, Apil 205, pg RESEARCH ARTICLE ISSN X Design of Micostip Antenna fo Wieless Local Aea Netwok Ram Kishan, D. Vijay Laxmi 2 ¹Reseach Schola, Guu Kashi Univesity, Talwandi Sabo (Bathinda), Punjab ²Dean, College of Compute Applications, Guu Kashi Univesity, Talwandi Sabo (Bathinda), Punjab amkishan_bansal@yahoo.co.in Abstact Moden wieless and mobile communication systems equies antenna which should have light weight, low pofile, low cost, and easy to be integated with RF devices. This demand is completed by micostip antennas. This pape pesents ectangula micostip patch antenna fo WLAN applications designed using IE3D softwae. The micostip antenna is designed with dielectic substate as Roges RT/duoid 5880(tm) with ɛ = 2.2. This antenna will wok on IEEE 802. WLAN 2.4 GHz band. The antenna is optimized to impove the pefomance measues like gain, etun loss and efficiency. The IE3D esult shows this antenna is suitable fo WLAN applications. Keywods Micostip, Antenna, WLAN, IE3D I. INTRODUCTION The micostip patch antennas ae widely used in WLAN applications because of its featues like low-pofile, compactness and high efficiency [, 5]. A micostip patch antenna is most often a /2 wavelength stuctue although it can also be made as a /4 wave element []. The patch antennas ae pinted on the top suface a 2-laye PCB, although sheet metal patches ove a gound plane with an ai-dielectic ae also in wide use. Patch antennas ae consideed diectional antennas with a pimay lobe of adiation ove an appoximately 70 x 70 degee secto (in the diection away fom the gound plane). Because of the diectional natue patch antenna may be an excellent choice fo a fixed-mount device on the side of building whee the adiation fom an omnidiectional antenna [4] would be wasted in the diection of the building. 205, IJCSMC All Rights Reseved 36

2 Fig. Stuctue of Micostip Antenna II. ANTENNA PERFORMANCE MEASUREMENTS To successfully design an antenna a numbe of measuements must be made to quantify the antenna pefomance [4]. Below ae the vaious antenna pefomance measuements. A. Impedance and Antenna Bandwidth Antenna impedance is typically measued as etun loss o VSWR [4]. The equipment used to measue this paamete is a Netwok Analyze. The impedance (and the bandwidth ove which the impedance is acceptable) must be measued with the antenna installed in the device with all components installed. The impedance measuement often equies special fixtues and assemblies to allow access to the antenna teminals. It is not uncommon that the antenna equies some small tuning adjustments when the device is finally fully assembled. At this stage, if the initial design was well done, most embedded antennas ae often quite easily tuned with small changes to the PCB layout o sheet metal pat, and/o with the addition of passive components on the antenna o the adio PCB. B. Gain and Radiation Pattens Calibated measuements of antenna gain and adiation pattens ae made in an Anechoic Chambe. The anechoic envionment eliminates all eflections and allows pecise and epeatable measuements to be made. The device unde test is typically otated 360 degees in multiple oientations to detemine the shape of the adiation patten fom many diffeent diections. Refeence antennas ae used as calibated gain standads. As with impedance measuements, gain and adiation pattens should be measued using a complete poduct. C. Efficiency Measuements As mentioned ealie, efficiency may be the single most impotant paamete to be measued, especially fo an embedded antenna which can have degaded efficiency due to its tight integation with the device. Efficiency can be calculated fom the calibated gain and adiation patten measuement but this can be a time-consuming effot. III. MICROSTRIP ANTENNA CALCULATIONS The ectangula micostip antennas ae made up of a ectangula patch with dimensions width (W) and length (L) ove a gound plane with a substate thickness (h) having dielectic constant (ε ). Thee ae numeous substates that can be used fo the design of micostip antennas, having thei dielectic constants usually in the ange of 2.2 ε 2. The ones that ae most desiable fo antenna pefomance ae thick substates whose dielectic constant is in the lowe end of the ange because they povide bette efficiency; lage bandwidth loosely bound fields fo adiation into space, but at the expense of lage element size [2]. The design of micostip patch antenna assumes that the specified infomation includes dielectic constant of substate (ε ), height of substate (h) and esonant fequency (f ) [3]. Afte specifying ε, f and h detemine the values of Width (W) and Length (L). Diffeent dimensions of ectangula micostip antenna [] ae calculated as follows: 205, IJCSMC All Rights Reseved 362

3 Fo good adiation efficiency the width is calculated as [] W f f Whee 0 is the fee-space velocity of light. The effective dielectic constant of micostip antenna given in [6] as eff h W 2 Expession of extension of length as in [7] is given by W ( eff 0.3) h L h W ( eff 0.258) 0.8 h Then actual length of patch can be calculated L 2L 2 f eff 0 0 IV. DESIGN OF ANTENNA Figue 2 and 3 shows the Initial shape of ectangula micostip antenna and its Optimized stuctue espectively. The geometical dimensions fo design of antenna ae length = 48.6 mm and width= 4.54 mm. The height of Roges RT/duoid 5880(tm) substate h=.58 mm and dielectic constant is 2.2. The effective dielectic constant (ɛ eff ) = 2.0 and xtension of lenght ( L) is mm. This patch antenna uses a coaxial line feed at distance of 26.2 mm with thickness of 5 mm. The esonant fequency is 2.4 GHz at which antenna will wok. Fig. 2 Rectangula Micostip Antenna Fig. 3 Optimized Stuctue of Rectangula Micostip Antenna 205, IJCSMC All Rights Reseved 363

4 V. SIMULATION RESULTS IE3D simulato [2] is used fo simulation and vaious esults of ectangula micostip antenna ae pesented in figue 4 to 9. Fig. 4 Retun Loss vesus Fequency plot Fig. 5 VSWR vesus Fequency plot Figue 4 plots the Retun Loss esults of the antenna. The Retun loss is -3.9 at 2.42 GHz fequency with lowe and highe cut off fequencies ae 2.38GHz and 2.46 GHz espectively. Figue 5 plots the VSWR (Voltage standing wave atio) esult. The VSWR vesus fequency cuve shows its value.6 at 2.42 GHz. Fig. 6 3D Radiation Patten Fig. 7 2D Elevation Patten Gain Display Figue 6 and 7 plots the Antenna gain. Figue 6 shows the 3D adiation patten and figue 7 shows 2D elevation patten gain display. Result shows ectangula micostip antenna gain is 7.2db at fequency 2.42GHz. The maximum gain of antenna in one diection is shown as diectivity is 7.6db as shown in figue , IJCSMC All Rights Reseved 364

5 Fig. 8 3D Diectivity Fig. 9 Antenna Efficiency plot Figue 9 shows the Efficiency vesus Fequency gaph. This gaph plots Antenna efficiency and Radiation efficiency. Result shows the 90%, 9% antenna efficiency and adiation efficiency at fequency 2.42 GHz espectively. This shows the antenna gives good pefomance at 2.4 GHz band. VI. CONCLUSION AND FUTURE WORK In this pape we design a ectangula micostip antenna fo WLAN application. The fequency band used fo antenna is IEEE 802. WLAN 2.4 GHz. Simulation is done with IE3D and esults shows good pefomance with antenna efficiency is 90%. The antenna achieves gain of 7.2db at 2.42GHz and its maximum gain in one diection is 7.6db. The etun loss esult shows -3.9 at 2.42 GHz. All these pefomance measue esults make this antenna suitable fo the WLAN applications. In futue we can design an antenna aay by joining numbe of antennas to incease the gain in all diections. REFERENCES [] Balanis C.A, Antenna Theoy: Analysis and Design, 3d Edition (Wiley India), 997. [2] R. Gag, P. Bhatia, I. Bahl, and A. Ittipiboon, Micostip Antenna Design Handbook, Atech House, 200. [3] Jayant G. Joshi, Shyam S. Pattnaik, Swapna Devi, Mohan R. Lohokae, Bandwidth Enhancement and Size Reduction of Micostip Patch Antenna by Magnetoinductive Waveguide Loading, Wieless Engineeing and Technology, Vol. 20(2), pp [4] Antenna Fundamentals Technical Bief, AT & T, [5] Anil Kuma Agawal, Shyam Sunde Pattnaik, S Devi, J G Joshi, Boadband and high gain micostip Patch Antenna fo WLAN, Indian jounal of Radio and Space Physics, Vol. 40, Octobe 20, pp [6] C. A. Balanis, Advanced Engineeing Elctomagnetics, John Wiley and Sons, New Yok, 989. [7] E. O. Hammestad, Equation fo Micostip Cicuit Design, Poc. Fifth Euopean Micowave confeence, pp , Septembe 975. [8] A. H. Ramadan, K. Y. Kabalan, A. El-Hajj, S. Khouy and M. Al-Husseini, A Reconfiguable U-Koch Micostip Antenna fo Wieless Applications, Jounal of Pogess In Electomagnetics Reseach, Vol. 93, pp , [9] Xu-bao Sun, Mao-yong Cao, Jian-jun Hao, Yin-jing Guo, A ectangula slot antenna with impoved bandwidth, Intenational Jounal of Electonics and Communications (AEÜ), 66 (202) [0] Yiming Li, Simulation-based evolutionay method in antenna design optimization, Mathematical and Compute Modelling, Vol 5, pp , 200. [] I. J. Bahl and P. Bhatia, Micostip Antennas. Atech House, Dedham, MA, 980. [2] IE3D Use Manual, Zealand Softwae. 205, IJCSMC All Rights Reseved 365