Design and Simulation of Fractal Antenna with DGS structure for Multiband Applications

Transcription

1 Design and Simulation of Fractal Antenna with DGS structure for Multiband Applications Yogesh A. Rakhunde 1, Prof. Surekha K.Tadse 2 1 Research Scholar, Department of Electronics and Telecommunication, G. H. Raisoni college of Engineering, Nagpur, India 2 Assistant Professor, Department of Electronics and Telecommunication, G. H. Raisoni college of Engineering,Nagpur, India Abstract In this paper, square shaped fractal antenna is proposed by modifying the basic design structure of antenna. The antenna is designed by cutting the corner edges of square patch in a fractal manner. Fractal geometry is initiated to obtain the multiple resonance frequency applications and to achieve compact structure design and low profile antenna. The basic square patch structure is selected and three iterations with defective ground plane are simulated on HFSS.The increase of the iterations of fractal antenna no of resonances increases. The proposed fractal antenna includes Defective-Ground have multiband resonance response over the range of frequencies from 0Ghz to 15Ghz.The simulation results obtained for this antenna are 3.4Ghz,4.39Ghz,9.90Ghz,10.75Ghz and 14.43Ghz.The simulation results prove that the antenna can find its use multiband applications. The designed antenna is analyzed on the basic antenna parameters like return Loss, Gain,, directivity and bandwidth. Keywords Fractal, Fractal Antenna, Patch, Defective-Ground, DGS, Multiband, Multi-resonance. I. INTRODUCTION In the modern wireless communication systems and miniaturizing the size of antennas, there is a extreme need of antennas having compact size and multi-resonance characteristics. In the era of wireless communication system there is a great need of small size antennas for commercial applications. These antennas also find their use in military and RADAR applications. Multiband characteristics of fractal antenna allows user to use single antenna device to operate over several number of frequency bands. Fractal antennas are introduced to have a single antenna which provides multi-resonance response over multiple bands of frequencies. The commercial operators are going for an antenna system which possesses good performance characteristic like low profile design,multi-resonance response and low cost. All these requirements of the operators are fulfilled by Microstrip fractal antenna. Microstrip antennas have many advantages over simple microwave antenna design. They possess properties like low profile, Compact size, Multi-resonance and low cost. The size of the conventional Microstrip antenna is not manageable for modern wireless communication equipments. The reduction in the size of Microstrip antenna without affecting the performance parameters of conventional Microstrip antenna is extremely important in wireless communication. This paper presents a design of multiband fractal antenna with defective ground plane. II. FRACTAL ANTENNAS AND DGS Fractal antenna applies a fractal geometry technique invented by Benoit Mandelbrot in 1975.Fractal antenna is a antenna with irregular shape and self similar pattern design. It is designed to increase the perimeter of patch material which can radiate within a total surface area of the patch fractal geometry design affords for the improvement of the antenna array and increase in the number of resonance frequencies without affecting key parameters of All Rights Reserved 402

2 Fractals have parameter which repeats them according to their iteration factor. Iteration factor depends on the fractal geometry design considerations. Fractal structures are introduced to obtain higher order structure to cover more number of frequency bands. Fractal antenna design structure is a solution to reduce the physical shaped and size of antenna. Fractals have some unique properties and features:- Fractal set has low profile structure. Fractals have self similar property. They have multiband and multi-service feature. They offer improved gain and bandwidth within the less physical shape. They are more reliable and have low cost than other conventional antennas. The Defective-Ground is used to modify design for reduction in physical area of the antenna. III. PROPOSED ANTENNA STRUCTURE The square shaped Microstrip patch fractal antenna is proposed in this work to get the multi service and multiband operations. The basic design for antenna is selected on the types of natural design shapes available for fractal patch antenna. The higher order design structure is obtained through the fractal generation technique. A. Fractal generation technique The fractal shaped can be constructed through repeating the iteration on the basic design structure. In this simulation work the "square" shape patch is selected as a basic block for antenna design. The Iterations which are applied in this design are followed by these steps:- Step 1: Squared patch is divided into small nine square with the iteration factor of one by three. Step 2: Cut the squares from each corners to get the plus-shaped design. Step 3: Applies Step1 followed by Step2 to every square generated except middle one. Step 4: Apply DGS structure and addition of slots to improve gain and bandwidth. B. Iterations of Fractal structure Iterations are the repetitive tasks done on the basic structure to get the fractal shape design. The high order antenna structure is obtained by applying the iteration procedure technique on the basic square patch structure. The basic iteration is initially applies within a original square. It results in generating number of squares with the iteration order equal to one. The same procedure is applicable on all remaining iterations The Fig 1.shows the iterations steps for the generation of higher-orders fractal shape antenna. Fig.1.Iterations of the fractal All Rights Reserved 403

3 This design is a miniaturized compact antenna design to obtain multiband characteristics with reduced physical shape. IV. ANTENNA DESIGN CONSIDERATIONS For this design, the basic resonance frequency selected is 2.6Ghz.Antenna design analysis is doe on the basic square shape structure design. The dimensions for the proposed antenna are calculated by following given equations. L is Patch-length and W is Patch-width and λd refers to wavelength of dielectric. (1) (2) refers to Relative-permittivity substrates whereas λ refers to wavelength, where (3) f is value of resonance selected and C refers to light s speed. The Patch dimensions for antenna design are calculated to be 27mm from equation (1).The 27mm square patch design is selected for the resonance frequency of 2.6Ghz.The iteration factor for this design is taken to be the one-third of the original shape to get the desired fractal geometry. The symmetry property of antenna is also achieved by taking the iteration factor equal to 1/3.The total number of iterations are selected to be three in order to get 1mmwidth fractal patch at 3rd order iteration. The design considerations of the design are shown with the values in TABLE 1. TABLE. 1.Design considerations. Parameters Values Patch-Length 27mm Patch-Width 27mm Substrates-Thickness 1mm Name of Substrate FR-4 Dielectric-Value 4.4unit Feed-Point (13.75,7.25,-2) Feeding Technique Co-axial Feeding Technique The dimensions of the designed structure are shown in Fig.2 All Rights Reserved 404

4 (b) (c) (d) (e) Fig.2. Designs for Patch,(a)0 th orders, (b)1 st orders, (c)2 nd orders, (d)3 rd orders and (e)3 rd orders modified. This design of antenna is initially iterated for the resonance of 2.6Ghz.The Fig. 2 shows the iterations order of designed antenna. The fractal patch is iterated with the iteration factor of All Rights Reserved 405

5 3 rd order iteration is modified by insertion of fractal shaped slots in the design to improve the overall gain for antenna. The 3D model-view of fractal antenna is described below in Fig.3. Fig.3.3D view of antenna structure. V. SIMULATION RESULT AND ANALYSIS All the antenna structures are simulated using Ansoft HFSS Version 13.0 software. For 0 th iterations resonance frequency obtained after all the simulations is at 2.69Ghz with gain of db.For 1 st order of iteration, the resonant frequencies are 2.9 GHz and 3.6 GHz with a gain of db and db respectively. The 2 nd order iteration gives the resonance at 4.25 GHz, 9.62GHz and 13.86GHz with a gain of db,-15.39db and db respectively. The 3 rd order iteration provides resonance at 4.39GHz, 10.05GHz, GHz, GHz with the values of gain are db,-19.22db,-14.72db and db respectively. The modified 3rd order of iteration gives the maximum five resonant frequencies which are at 3.26, 4.25, 9.76, and GHz with a gain of db,-14.59db,-15.16db,-21.56db and db.The simulated S-parameters results for different iterations are described in the figures below Fig.4. 0 th order S-parameter (Return loss) All Rights Reserved 406

6 Fig 5. 1 st order S-parameter (Return loss) m Fig nd order S-parameter (Return loss) m m m m3 m Fig.7. 3 rd order S-parameter (Return loss) m m m m3 m m Fig.8. Modified 3 rd order S-parameter (Return loss) TABLE 2.NUMBER OF RESONANCE FREQUENCIES WITH ITERATION ORDER Iterati ons Numbe rs Resonance Frequencies for iterations in GigaHertz. f0 f1 f2 f3 f All Rights Reserved 407

7 Iterati ons Numbe rs. Resonance Frequencies for iterations in GigaHertz. f0 f1 f2 f3 f The plot of antenna is analyzed to get the impedance matching compatibility of antenna. As for this design we are using coaxial feeding, it is necessary that the value of should be below unit value 2. The Values for the resonance frequencies of 3 rd order modified iteration for 3.26GHz, 4.25GHz, 9.76GHz, 10.33GHz and 13.86GHz are 1.61, 1.45, 1.42, 1.18 and 1.31 respectively. The simulation results of the for different iterations are described in following figures Active(coax_pin_T1) Fig th orders Active(coax_pin_T1) Fig st orders m Active(coax_pin_T1) m3 Fig nd All Rights Reserved 408

8 International Journal of Recent Trends in Engineering & Research (IJRTER) m m Active(coax_pin_T1) m4 m3 Fig rd orders m m m Active(coax_pin_T1) m4 m3 m5 Fig.13. Modified 3 rd orders The radiation pattern of antenna is depends on the directivity plot.thedirectivity of antenna determines the direction of the raditions of the antenna. The directivity plot for the modified 3 rd order iteration is shown in Fig 14. Directivity 0 Curve Info db(dirtotal) Setup1 : Sw eep Freq=' GHz' Phi='0deg' db(dirtotal) Setup1 : Sw eep Freq=' GHz' Phi='0deg' Fig.14. Radiation pattern of Antenna VI. CONCLUSIONS The fractal antenna simulation in carried out on HFSS software version 13.0.The results are analyzed for different operating frequencies in the range of 0.1GHz to 15GHz. With increase in orders of iterations, the number of resonant frequencies is increased by one. The antenna finds its use in multi-service applications. At last, numbers of resonant frequencies are five in modified third iteration. Feature of improved gain is achieved by reducing the size of ground plane. The reinforced gain is obtained at one fourth ground plane as compared to typical ground structure. The antenna gives the best result at two resonant frequencies 2.56 GHz and 3.5 GHz. REFERENCES 1. B. B. Mandelbrot, The Fractal Geometry of Nature, New York, W. H. Freeman, Anoop S.R, Ajayan K.K, Dr.M.R.Baiju, Krishnakumar, Multiband behavioural Analysis of a Higher Order Fractal Patch Antenna,IEEE International Congress On Ultra Modern Telecommunication and Control Systems and All Rights Reserved 409

9 3. C. Puente-Baliarda, J. Romeu, R. Pous, and A. Cardama, On the behavior of the Sierpinski multiband fractal antenna, IEEE Trans. Antennas Propag., vol. 46, no. 4, pp , Apr Ghani, C.Z.C.; Wahab, M.H.A.; Abdullah, N.; Hamzah, S.A.; Ubin, A.; Dahlan, S.H.; Anuar, A.K.; Ramli, K.N.; Alwi, M.F., "Design Sierpinski Gasket Antenna for WLAN Application," Microwave Conference, APMC, Asia-Pacific, pp.1,4, Dec Douglas H. Werner and Suman Ganguly, An Overview of Fractal Antenna engineering Research, IEEE Antennas and Propagation Magazine, Vol 45, No 1, February W.L. Chen and G.M. Wang, Small size edge-fed Sierpinski carpet microstrip patch antenna, PIERS C, Yol.3, , S. Sheik Mohammed, K. Ramasamy, and T. Shanmuganantham, A 2.45GHz Sierpinski Carpet Edge-fed Microstrip Patch Fractal Antenna for WPT Rectenna IEEE International Conference on Communication Control and Computing Technologies (ICCCCT), pp.57,60, 7-9 Oct Yao Na and Shi Xiao-wei, Analysis of multiband behavior on sierpinski carpet fractal antennas, Microwave Conference Proceedings, APMC Asia-Pacific Conference Proceedings, vol.4, Dec Kalaimani, T.; Venkatesh, P.M.; Mohanamurali, R.; Shanmuganantham, T., "A modified Sierpinski carpet fractal antenna for wireless applications," International Conference on Communications and Signal Processing (ICCSP), 2013, pp , 3-5 April Hussain, R.; Sheikh, S., "Feed point optimization of a microstrip sierpinski carpet antenna," 3rd IEEE International Conference on Computer Science and Information Technology (ICCSIT), vol.5, pp , 9-11 July Bin Shi; Zhiming Long; Jili Wang; Lixia Yang, "Design and analysis of a modified Sierpinski Carpet fractal antenna for UWB applications," Proceedings of the International Symposium on Antennas & Propagation (ISAP), vol.01, pp , Oct A. Falahati, M. Naghshvarin-Jahromi, R. M. Edwards, Bandwidth enhancement and decreasing ultra-wideband pulse response distortion of Penta-Gasket-Koch Monopole antennas using compact-grounded co-planar wave guides, IET Microwave antenna and propagation, vol. 5, no. 1, pp , All Rights Reserved 410