Design of Sierpinski Carpet Fractal Antenna Using HFSS

Transcription

1 e-issn: p-issn: 31-63X Design of Sierpinski Carpet Fractal Antenna Using HFSS Sneha U 1 V N V Varun L V Abhilash 3 Rasheed S 4 (sneha16993@gmail.com) (varunvnv.7@gmail.com) (abhi @gmail.com) (bunny.rasheed@gmail.com) A.Gayarti 5 Dr Sreenivasa Rao Ijjada 6 (gayatriallu@gitam.edu) (isnaidu3@gitam.edu) Dept of C, GIT, GITAM University, Visakhapatnam Abstract With the encroachment of wireless communication in the last few decades has made the technology more affordable. This escalating attractiveness of wireless communication devices capable of high-speed transfer rate has prompted the need of developing efficient broadband antennas. The incredible increase in wireless communication in the last few decades has led to the need of antennas with increased bandwidth, gain and low profile. One such technique to achieve wideband/multiband antennas is by applying fractal shape into antenna geometry. Fractals, through their selfsimilar property, are natural systems where this complexity provides the sought after antenna properties. Fractal Antennas radically alter the traditional relationships between bandwidth, gain and size, permitting antennas that are more powerful, versatile and compact. The designed antennas can be used for various applications such as military and meteorological satellite communication (8 to 1.5 GHz), Wi-Fi ( GHz), PTP communication in US military (6 GHz), radar and navigation services. Keywords: Microstrip Antenna, Fractal, Sierpinski Carpet Fractal Antenna (SCFA), Antenna Arrays, HCR principle I. INTRODUCTION Over the last decade the wireless communication systems kept fascinating the engineers, hence receiving a lot of attentions because of their inherent advantages such as convenience, low cost and ease of fabrication. Wireless Local Area Networks (WLAN) are being universally recognised as a compact, flexible, economic and high speed data connectivity solution. This leads to an outgrowth of micro strip patch antennas. Table 1.1 demonstrations the operating frequency ranges of some of the most frequently used wireless communication systems. System Advanced Mobile Phone Service (AMPS) Global System for Mobile (GSM) Personal Service (PCS) Global System for Mobile (GSM) Wideband Code Division Multiple Access (WCDMA) Universal Mobile Telecommunication Systems (UMTS) Ultra Wideband (UWB) Overall Frequency Tx: Rx: Tx: Rx: Tx: Rx: Tx: Rx: Tx: Rx: -17 Tx: Rx: -17 Tx: Bandwidth 7 (8.1%) 8 (8.7%) 17 (9.5%) 14 (7.3%) 5 (1.%) 5 (1.%) 75 (19%) Table 1.1 Wireless Spectrum IJI 4

2 e-issn: p-issn: 31-63X Microstrip antenna offers numerous advantages as well as some disadvantages compared to the conventional one. The disadvantage includes lower gain, excitation of surface waves, narrow bandwidth, high quality factor (Q), Ineffective use of available physical area and low power handling due to its smaller size. Researchers proposed several approaches to shrunken the antenna size, enhancement in bandwidth by decreasing the quality factor. Today s small handheld devices challenge antenna designers for ultrathin, convenient and high performance devices that have the capability to meet the multi standards. This feature emerged antenna examination in different ways; one of the methods is the use of fractal shaped geometry. Fractal is a concept extension to the microstrip antenna. Fractals will expand the bandwidth and shrunken the parameter dimensions of the antenna. Fractal Geometries: Fractals are used to define structures whose dimensions are not whole number. Fractal geometry is that branch of study which deals with properties and behaviour of fractals. These geometries have been used to characterise objects in nature that are difficult to define with the help of uclidean geometries including length of coastlines, branches of trees etc. Fractals represent a class of geometry with properties including: Self-similarity Fractional dimension Formation by iteration Plane filling nature Fig Hohlfield-Cohen-and-Rumsey(HCR) Conditions The microstrip antenna was designed with the help of equations from Balanis [1] II. MATRIALS AND MTHODOLOGY: The works performed in this project is: 1) Design of Micro strip Antenna ) Plots of Radiation Pattern,S, VSWR of Micro strip Antenna 3) Incorporation of Slots into Micro strip Patch Antenna (up to 1 st Iteration) 4) Radiation Pattern, S, VSWR plots for the 1 st iteration. 1) Design of Micro strip Antenna: The antenna parameters are designed using the following equations: W = c fo r + 1 r + 1 r 1 = ΔL =.41h h w 1/ w h w h (i) (ii) (iii) Fig 1 : Sierpinski Carpet Antennas upto 3rd iterations L eff c = (iv) f IJI 5

3 e-issn: p-issn: 31-63X L = Leff ΔL (v) W g =1 h + W (vi) L g = 1 h + L (vii) L n = A n = 1 3 n n * (xiv) (xv) ) Radiation Pattern, S, VSWR of Micro strip Antenna: III. RSULTS The radiation pattern for the micro strip antenna is calculated from the following equations A. MICROSTRIP ANTNNA: k f = (viii) 3 R r 1* λ = k * 1 h 4 (ix) 3 f λ = (x) ( θ ) k h kl sin *cosθ *cos *cosθ *cos = k h θ ( θ ) max( ( θ )) (xi) max = (xii) ( θ ) ( θ ) max ( θ ) = (xiii) nor Fig.3-Design of micro strip antenna The Microstrip antenna is designed according to the design equations stated in methodology. B. Plot of S v/s Frequency : VSWR 1 S 1+ S = (xiv) 3) FIRST AND SCOND ITRATION : The generalized formulas for iteration n are as follows: N n = The number of black box. L n = The ratio for length. A n =the ratio for the fractal area after n th iteration. Fig.4- Plot of S v/s Frequency The plot is between frequency on x-axis and return loss ( S ) on y-axis. The resonant frequency is found to.45 GHz n= the iteration stage number. N n =8 n (xiii) IJI 6

4 e-issn: p-issn: 31-63X C. Plot of VSWR V/S frequency : G. Plot of S v/s Frequency after 1 st iteration: D. Fig.5 - Plot of VSWR v/s Frequency The above is the plot of VSWR v/s frequency and the VSWR quals near at resonant frequency.. Plot Of -D Radiation pattern : Fig.8- Plot of S v/s Frequency after 1 st iteration The plot is between frequency on x-axis and return loss ( S ) on y-axis. The resonant frequencies are found to be 3.7Ghz, 4.1Ghz, 4.7Ghz, 5.94Ghz, 6.36Ghz, 6.81Ghz, 7.Ghz, 7.9Ghz, 9.48Ghz. H. Plot of VSWR V/S frequency after 1 st iteration : Fig.6- Plot Of -D Radiation pattern The above is the radiation pattern where there is maximum radiation when θ is equal to 9. F. Microstrip Antenna after incorporating 1 st slot: Fig.5 - Plot of VSWR v/s Frequency The above is the plot of VSWR v/s frequency and the VSWR quals near at resonant frequency. G. Plot Of -D Radiation pattern after 1 st iteration: Fig.7-First iteration of micro strip antenna The above figure is the after a slot is inserted which results in Carpet Fractal Antenna Fig.6- Plot Of -D Radiation pattern IJI 7

5 e-issn: p-issn: 31-63X The above is the radiation pattern where there is maximum radiation when θ is equal to 9. CONCLUSIONS In this work fractal concept is applied to microstrip patch antenna and sierpinski carpet fractal antenna upto third iteration. From the results obtained, it was evident that by applying fractal concept to microstrip antenna the antenna can resonate at multiple frequencies so the design antenna can be operated at multiple frequencies. As the iteration increases the gain of the antenna increases, thereby size of the patch is reduced upto 33%. RFRNCS [1] Rahul Batra, P.L.Zade & Dipika Sagne, "Design and Implementation of Sierpinski Carpet Fractal Antenna for Wireless ", International Journal of Scientific Research ngineering & Technology (IJSRT), Volume 1 Issue3 pp July 1. [] H. Rumsey, Frequency Independent Antenna (Academic Press, New York and London, 1966). [3] C.A.Balanis, "Antenna Theory - Analysis and Design", nd edition, John Wiley & Sons Inc., Foster, I., Kesselman, C.: The Grid: Blueprint for a New Computing Infrastructure. Morgan Kaufmann, San Francisco (1999). [4] Rogert R.T., Design of Microstrip fed Sierpinski carpet fractal antenna(scfa) upto third iteration upto third iteration [5] Swastika Singh,March 14, Fabrication of Sierpinski carpet fractal antenna ranges, International Journal of Scientific Research ngineering & Technology (IJSRT) [6] Ruchi Singh, Hamid Ali,July 14, Fractal techniques exhibited different fractal geometries for different applications. International Journal of Scientific Research ngineering & Technology (IJSRT) IJI 8