I. INTRODUCTION II. ANTENNA DESIGN

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1 International Journal of Advances in Engineering, 215, 1(4), ISSN: (printed version); ISSN: (online version); url: RESEARCH ARTICLE Design of Multiband Antenna on Pentagonal Patch by Using Minkowski Curve S.Suresh Subramanian and S.Selvarani Dept. of ECE, A.K.T Memorial College of Engineering and Technology, Kallakurichi, Tamil Nadu, India. Received 2 April 215 / Accepted 21 May 215 Abstract The multiband antenna is proposed on pentagonal patch by using Minkowski curve. The Microstrip patch antennas are widely used in telecommunication system due to its low profile and light weight. Several designs are made for Microstrip patch antenna with different patch shape to provide the multiband on certain size of antenna. Here we yet reduced the antenna size (4mm) and providing the K band. We are using fractal curve (Minkowski curve) to obtain the multiband with smaller size. The Minkowski curve is applied on both inside and outside of the pentagon. Length and width of the substrate is 4mm with thickness of 1.6mm, substrate material is FR4 (4.4). The bandwidth obtained is K band for iterative of pentagonal patch. Simulation is important before that the design is going to be fabricated for that we are using Ansoft HFSS. The application for this band is radar and satellite communication. Keywords Pentagonal patch, Minkowski-curve Multiband, Co-axial probe feeding. I. INTRODUCTION The recent telecommunication system require antenna with higher bandwidth and smaller size. The size of the existing microstrip patch antenna is large while designing at microwave frequency range that makes difficulty to use on transmitter and receiver [1]. The antenna is efficient when the antenna size is greater than wavelength/4 otherwise it is inefficient, the gain and bandwidth is reduced with decrease in antenna size [2]. The Microstrip patch contains three important element namely substrate, ground and patch, the patch is placed on the grounded substrate, it may be any possible shape. The bandwidth is directly proportional to substrate thickness and inversely proportional to dielectric constant of the substrate. The dielectric constants value normally in the range of 2.2 εr 12. These requirements are satisfied by the Fractal antenna, the fractal having self similar and space filing properties, the self similarity makes multiband operation due to it operate in same manner at different wavelength, the fractal are developed due to in-depth study of nature of patterns [3-4]. The greater integration electronics causes the communication devices to be smaller, the reduction of antenna size is necessary due to the antenna occupy larger part of overall package volume [5]. Though the Microstrip patch antenna having lot advantages it also having some disadvantages is narrow bandwidth and low gain [6]. The length of rectangular Microstrip patch antenna is.3333λ <L<.5 λ, the λ is free-space wavelength. The patch thickness is too lesser than λ and height of substrate is in the range of.3 λ.5 λ [7]. The substrate length of Microstrip patch antenna is depending upon length and width of the patch [1]. There are several Fractal curves and self similar have been used by researchers on different type of polygons up to octagon and provided some multiband and ultra wideband. Here the proposed Microstrip patch antenna designed on pentagonal patch by using Minkowski curve to provide same multiband with smaller dimensions. The length and width of substrate is 4 mm and thickness is 1.6 mm, substrate material is FR-4 with dielectric constant of 4.4. The Minkowski curve has applied on both inner side and outer side of the pentagon. The return loss and VSWR are calculated for base shape of pentagon and some iteration. II. ANTENNA DESIGN The antenna size is 4X4X1.6 mm; the side length of the pentagonal patch is 15mm with radius The formula used for assign the side length of any polygons is R= ( ) Here, R-> Radius of the pentagon S-> Side length of the pentagon N-> Number of faces on pentagon Here we are using co-axial probe feeding to feed the Microstrip patch antenna. It having two conductor, the side view of co-axial probe feeding is shown in Fig 1.we have selected the diameter of the two conductor using co-axial line calculator. The pec material is used for both inner and outer conductor. The inner and outer conductors are connected to the patch and the ground respectively.

2 563 Int. J. Adv. Eng., 215, 1(4), Figure.1 Side view of the co-axial probe feeding. The diameter of the conductor is selected to match the 5Ω impedance of the Microstrip patch antenna. For excitation of Microstrip patch antenna we are using the wave port. The base shape of pentagonal patch is shown in Figure.2 III. SIMULATION RESULTS ANALYSIS Figure.2 Base shape of pentagonal patch. Here we do not make any change on patch and ground, and then we observed the return loss of base shape of pentagonal patch. The return loss is shown in Fig 3. We also observed the VSWR (Voltage Standing Wave Ratio). The return loss value should be below -1 db and VSWR value should be below 2. Retturn loss in db base shape of pentagon Figure.3 The return loss of base shape of pentagonal patch. We have done the Minkowski first iteration on pentagonal patch (inner side) for improving the return loss value of Microstrip patch antenna that is shown in Fig 4.

3 564 Int. J. Adv. Eng., 215, 1(4), Figure.4 The Minkowski first iteration (inside) The Minkowski is applied on each side of the pentagon faces by considering the faces as the initiator. The initiator is divided into three equal parts and middle one is removed by the square. The return loss value is improved as compared to the base shape of pentagonal patch. Here also the same band is obtained but the depth is increased as shown in Fig 5. We also drawn the second iteration is shown in Fig 6. Here the band width is not improved hence we stopped the further iteration on inside of the pentagonal patch Minkowski First iteration(ins ide) -3 Figure.5 The return loss of first iteration. The Minkowski curve is applied on same pentagonal patch at outside and the return loss is observed. The Minkowski first iteration (outside) is shown in Fig 8. Here also the same band obtained but the return loss depth is improved as compared to the inside first iteration. Figure.6 Minkowski second iteration (inside)

4 565 Int. J. Adv. Eng., 215, 1(4), Frequency in db 2 4 Minkowsk i second iteration(i nside) Figure.7 The return loss of second iteration (inside) Figure.8 The Minkowski first iteration (outside) Finally the outside pentagon iteration provided the better band width as compared to other design; the comparison table and graph is given below Minkowski first iteration(out side) Figure.9 The return loss of first iteration (outside). Figure.1 Comparison of all iterations.

5 566 Int. J. Adv. Eng., 215, 1(4), Table 1: Comparison of different iteration Design Base shape of pentagonal patch Minkowski First iteration(inner side) Minkowski second iteration(inner side) Minkowski first iteration (outside) CONCLUSION Here the multiband antennas on pentagonal patch are presented at 19.7 GHz with return loss of db for Minkowski first iteration (outside). In future we will analyze same Minkowski curve for different polygon shapes. REFERENCES 1. Chakkit kamtongdee, Nantaken Wongkasen, A Novel Design of Compact 2.4 GHz Microstrip Antennas, IEEE, pp A.Azari, Ultra Wideband Fractal Microstrip Antenna Design, Progress In Electromagnetics Research C, vol.2, pp.7-12, D. H. Werner and S. Ganguly, An Overview of Fractal Antenna Engineering Research, IEEE Antennas and propagation Magazine, vol.45, pp Saira JOSEPH, Binu Paul, shanta MRIDULA, Penzholi MOHANAN, A Novel Fractal Antenna With CPW Feed for Multiband Applications, Radio Engineering,Vol.22, No.4,December B.SAI SANDEEP, S.SREENATH KASHYAP, Design and Simulation of Microstrip patch Array Antenna for Wireless Communication at 2.4 GHz, International Journal of Scientific & Engineering Research, Vol.3, Nov Bimal gray, Rahul Verma, Ankit Samadhiya, Design of Rectangular Microstrip Patch Antenna Incorporated with Innovative Metamaterial Structure for Dual band Operation and Amelioration in patch Antenna Parameters with Negative μ and ε, International Journal of engineering Technology, pp , Ratika V.Chaudhari, Ila parmar, Review on Technologies for Microstrip Patch Antenna Gain & Bandwidth Enhancement, International Journal of Engineering and Innovative Technology, Vol.2, pp.1492, March (213). 8. Mohammad Naeem Iqbal, Hamood-Ur-Rahman, and Syeda Fizzah Jilani, An Ultrawideband Monopole Fractal Antenna with Coplanar Waveguide feed, International Journal of Antennas and Propagation, pp.1-7, Santanu Mondal and Partha P.Sarkar A Novel Design of Compact Wideband Hexagonal Antenna, Microwave and Optical Technology Letters, Vol.55,pp.1-4, January Arpit Nagar, Khem singh Solanki Design & and Analysis of Microstrip Patch Antenna, International Journal of Scientific Research in network Security and Communication, pp.1. March-April 213.