Volume No - 5, Issue No 5, September, 017 A Novel Multiband Fractal Antenna for X Band Communication Pushkar Mishra I K G Punjab Technical University Jalandhar, India E-mail: pushkarmishra1985@gmailcom Shyam Sunder Pattnaik National Institute of Technical Teachers Training & Research, Chandigarh, India E-mail: profshyampattnaik@gmailcom Abstract: In this paper, a new parallelogram shaped fractal antenna has been presented and discussed The proposed antenna follows the selfsimilarity property of fractal structure The patch having shape of parallelogram has the outer dimension of 30 mm 0 mm 50 mm 0 mm The antenna resonates at three different resonant frequencies at 70 GHz, 86 GHz and 11395 GHz with gain of 181158 db, 1346 db and 4638 db respectively The antenna is fabricated using FR-4 substrate with resonance at 705 GHz, 815 GHz, 877 GHz and 1065 GHz The simulated and measured results show good agreement Keywords: Fractal Antennas, Multiband, Iterations,, parallelogram the miniaturized fractal patch, where the borders along the I INTRODUCTION resonant length is square fractal, has been analyzed in The multiband behavior of fractal antenna has been introduced and discussed in [1] Self-similarity is a property common to many fractals, but in order to become a useful radiator, it is necessary that the fractal antenna meet the specifications at the desired frequencies such as high gain, high bandwidth, high directivity etc as suggested by [] Fractal structure is characterized by self-similarity property in which an object is being repeated on a scaling factor This means that a given fractal geometry is built up of a series of differently scaled smaller objects that bear the same form as the final construction These properties show that fractal geometries are self-similar objects having scaling factor in the design and obey space filling curves property in the design [4] The miniaturization effect on the fractal microstrip antenna is based on lengthening the surface current lines in the patch ingredient Asa result, the electrical length of the resonator is expanded and the entire structure can be miniaturized The behavior of miniaturized fractal patches, where the edges along the resonant length isa tom square fractal, has been studied in [5] Thus, the fractal geometry allows miniaturization of radiators with small overall dimensions Thus, the miniaturization effect on the fractal microstrip antenna is based on lengthening of the surface current lines in the patch element As a consequence, the electrical length of the resonator is expanded and the entire social organization can be miniaturized [6]The demeanor of [7]Fractal structures are brought forth by the Iterated Functions System (IFS), which is influenced by RES Publication 01 Page 11 wwwijmeceorg = n n+1 (1) In this article, a new parallelogram based design has been presented The simulated antenna is fabricated and tested The measured results have been compared with simulated results and antenna is mathematically validated Part II describes the intent of the fractal geometry, whereas section III depicts the simulated and measured results of the proposed antenna The result is discussed in section III and paper is concluded in section IV II ANTENNA DESIGN Figure 1 describes the final geometry of the proposed fractal structure having one iteration of performance The two triangular slots have been done on the patch with the scaling factor of 1/5 At the middle of the plot, a parallelogram has been switch off with the scaling factor of 05The antenna is designed in such a way that final geometry is established on a parallelogram shaped antenna with two triangular slots and one parallelogram slot, so in order to increase the electrical length of the antenna thus proving design as fractal geometry These slots in the antenna design give rise to multiband behavior of the antenna as will be shown in the results section The proportions of the parallelogram shaped patch antenna are: Length LA = 30 mm, LB = 50 mm; and width WA = WB
Volume No - 5, Issue No 5, September, 017 = 0 mm for the main microstrip parallelogram based patch antenna Since the slots of triangular shaped and parallelogram shaped has been cut from the main patch to design fractal geometry, the dimensions of the inner parallelogram are: L C = 15 mm, L D = 5 mm; and width W C = W D = 10 mm (by taking scaling factor of 05) The dimensions of the two inner equilateral triangles T 1 & T are: Length = 10 mm respectively for both the triangles The proposed antenna is fed by using a coaxial feeding technique (which is appropriate feeding as it is in the maximum electric field) at position x = -16 mm and y = 34 mm respectively The antenna is designed using FR-4 substrate having thickness h = 15676 mm; and dielectric constant ε r = 44 The geometrical construction of this fractal antenna starts with a patch of parallelogram shaped design which is depicted in figure (Base Design)By taking in two slots of triangular shaped pattern and one parallelogram shaped design, the first iteration is performed as indicated in figure 1 (first iteration) The scaling factor used is 05 for cutting all the slots The parallelogram shaped fractal antenna with 1 st iteration is depicted in figure 1 Figure 3 shows the final design and iteration process of proposed fractal geometry The resonant frequencies can be computed as [4] f 1 = c ε eff L () The gap between main design and triangular slot is G A = 5 mm and between triangle and parallelogram, the gap is G B = 75 mm respectively Figure1 Parallelogram shaped fractal antenna with 1 st iteration Figure Base design of parallelogram shaped fractal antenna Where c = free space velocity of light Mathematically, length of antenna is calculated as [5] -[6] -[7] l = c f r ε eff ΔL(3) ε eff = ε r +1 + ε r 1 ( 1 1+1 d W ) (4) The Width (W) is calculated by using equation W = c f r ε r +1 (5) The extended length of the patch is calculated using the equation [8] -[9] - [10] ΔL = 041d ε r +03 ( W d +064) ε r 058 ( W d +08) (6) Figure3 Iteration Process of parallelogram shaped fractal antenna (a) Base Design, (b) First Iteration From the structure, it is seen that addition of two triangular shapes (of same dimensions) give rise to self-similarity property and parallelogram slot give rise to space filling curve of fractal antenna, which are the most important characteristics of the fractal geometry Due to slots, electrical length of the antenna is increased which in turns increases the multiband frequencies, which is due to the fact that the path of current increases thereby increasing the resonance at different points on the patch As impedance is matched at a number of points, multi-frequency response takes place The proposed parallelogram shaped fractal antenna is simulated using HFSS Figure 4a and 4b show the photograph of top and back view of fabricated parallelogram shaped fractal RES Publication 01 Page 1 wwwijmeceorg
Volume No - 5, Issue No 5, September, 017 antenna Vector network analyzer is utilized to evaluate the return loss parameter of the fabricated fractal antenna Figure4a Photograph of radiation patch of proposed fractal antenna to higher order harmonics frequencies other than resonant frequencies has been present, which can be neglected for the purpose The antenna is fabricated using FR-4 substrate The comparison of simulated and measured return loss pattern is shown in figure 6 From figure 6, the measured return loss frequencies are 705 GHz, 815 GHz, 877 GHz and 1065 GHz at -197308 db, -13047 db, -15407 db and 1709 db magnitude respectively Both the simulated and measured return loss pattern shows good agreement Figure 7 & figure 8 depicts the elevation and azimuth pattern of the proposed fractal antenna Figure6 Comparison of Simulated and Measured Return Loss Pattern of Parallelogram Shaped Fractal Antenna with 1 st Iteration Figure4b Photograph of back view of proposed fractal antenna III RESULTS & DISCUSSION Figure 5 describes the return loss pattern of the simulated parallelogram shaped fractal antenna for 1st iteration Figure5 Return loss of Parallelogram Shaped Fractal Antenna with 1 st iteration The figure 5 depicts that the parallelogram shaped fractal antenna resonates at three different frequencies viz 700 GHz, 860 GHz and 11395 GHz at -56931 db, -3645 db, and -95847 db respectively The three resonant frequencies are the result of fractal geometry In figure 5, due Figure7 Elevation radiation pattern of the Parallelogram Shaped Fractal Antenna with 1 st iteration The gain of the proposed antenna at resonant frequencies is 181148 db, 1346 db, 4638 db at 70 GHz, 86 GHz and 11395 GHz respectively The peak directivity of the proposed antenna is 4490 db, 43993 db, 64560 db at φ=0 0 and θ=0 0 (where φ is azimuth angle and θ is elevation angle) Figure 9 shows the directivity of proposed antenna Table I shows the simulated and measured return loss with gain of parallelogram shaped fractal antenna with 1 st iteration Table II depicts the antenna parameters such as radiated RES Publication 01 Page 13 wwwijmeceorg
Volume No - 5, Issue No 5, September, 017 power, accepted power, radiation efficiency at three different frequencies Table II Parameters of Parallelogram Shaped Fractal Antenna with 1 st Parameters Radiated Power (W) Accepted Power Radiation Efficiency (70 GHz) Iteration (86 GHz) (11395 GHz) 0505064 0375797 0660171 099773 0995317 099887 0506445 0377565 0660918 IV CONCLUSION Figure8 Azimuth Radiation Pattern of Parallelogram Shaped Fractal Antenna with 1 st Iteration The proposed parallelogram shaped fractal antenna resonates at three distinct frequencies having sufficient gain The simulated and measured results shown are in full accord with each other The parallelogram shaped fractal antenna is directive antenna The antenna finds its application in X-band communication The gain of antenna can further be enhanced by doing Meta material loading on the fractal structure REFERENCES Figure9 Directivity of Parallelogram Shaped Fractal Antenna with 1 st Iteration SNo TableI Simulated and Measured Return Loss S11 Simulated (GHz) S11 Measured (GHz) Gain (db) 1 70 705 181148 86 815 877 1346 3 11395 1065 4638 [1] Carles Punte Baliarada, Carmen Borja, Mònica Navarro Rodero, Jordi Romeu Robert, An iterative Model for Fractal Antennas: Application to the Sierpinski Gasket Antenna, IEEE Transactions on Antennas and Propagation, Vol 48, No 5, pp 713-719, May 000 [] Jordi Romeu and Jordi Soler, Generalized Sierpinski Fractal Multiband Antenna, IEEE Transactions on Antennas and Propagation, Vol 49, No 8, pp 137-139, August 001 [3] CTP Song, Peter S Hall, H Ghafouri, Perturbed Sierpinski Multiband Fractal Antenna With Improved Feeding Technique, IEEE Transactions on Antennas and Propagation, Vol 51, No 5, pp 1011-1017, May 003 [4] J Guterman, AA Moreira and C Peixeiro, Dual-Band Miniaturized Microstrip Fractal Antenna for a Small GSM 1800 + UMTS Mobile Handset, IEEE MELCON, pp 1-15, May 004 [5] Kuldip Pahwa, Pushkar Mishra, H P Sinha, S S Pattnaik & J G Joshi, Design & Development of Diamond Shape Fractal Antenna for Wireless Communication, International Journal of Microwave & Optical Technology, Vol 7, No, pp 101-106, March 01 [6] J Gianvittorio and Yahva Rahmat-Samji, Fractal Antennas: A Novel Antenna Miniaturization Technique and Applications, Vol 44, No 1, pp 0-36, February 00 [7] Pushkar Mishra, Shyam Sunder Pattnaik & Balwinder Singh Dhaliwal, Modified Concentric Rings Based Square Shaped RES Publication 01 Page 14 wwwijmeceorg
Volume No - 5, Issue No 5, September, 017 Fractal Antenna for Wi-Fi & WiMAX Application, International Journal of Electronics Engineering Research, Vol 9, No 7, pp 1005-101, 017 [8] MF AbdKadir, AS Jaafar, MZA Abd Aziz, Sierpinski Carpet Fractal Antenna, Asia-Pacific Conference on Applied Electromagnetic Proceedings, Melaka, Malaysia, December 4-6, 007 [9] JosepParron Granados and Jordi SolerCastany, Dual Band Antenna with fractal Based Ground Plane for WLAN Application, IEEE Antennas and Wireless Propagation Letters, Vol 8, pp 748-751, 009 [10] J Gianvittorio and YahvaRahmat-Samji, Fractal Antenna: A Novel Antenna Miniaturization Technique and Applications, IEEE Antennas and Propagation Magazine, Vol 44, No 1, pp 0-36, February, 00 AUTHOR S BIOGRAPHIES Pushkar Mishra received MTech degree in Electronics and Communication Engineering in 010 He had also done his MSc Physics from HNB Gahrwal University, Uttarakhand in 008 Since 01 he is pursuing PhD in Electronics and Communication Engineering from Punjab Technical University, Jalandhar, under the guidance of Prof Dr Shyam S Pattnaik His research area includes Microstrip patch antennas, metamaterial antennas and fractal antennas Shyam S Pattnaik received PhD degree in Engineering from Sambalpur University, India in 01 Joined as a faculty member in Dept of Electronics And Communication Engineering at NERIST, India in the year 1991 He worked in the department of electrical engineering, University of Utah, USA under Om P Gandhi From 004 to 015, He has worked as Professor and Head of Educational Television Centre of National Institute of Technical Teachers Training and Research, Chandigarh He has acted as Vice-Chancellor, BijuPattnaik University of Technology, Rourkela, and OdishaPresently, he is Director of National Institute of Technical Teachers Training and Research, ChandigarhHe is recipient of National scholarships, Boyscast Fellowship, SERC visiting Scholarship, INSA visiting Scholarship, UGC visiting Scholarship, UGC visiting Scholarship and Best Paper Awards etc [11] [1] [13] [14] [15] [16] [17] [18] [19] [0] [1] [] [3] [4] [5] [6] [7] [8] [9] [30] [31] [3] [33] RES Publication 01 Page 15 wwwijmeceorg