Microstrip Patch Antenna with Fractal Defected Ground Structure for Emergency Management Sushil Kakkar 1, T. S. Kamal 2, A. P. Singh 3 ¹Research Scholar, Electronics Engineering, IKGPTU, Jalandhar, Punjab, India ²Professor, ECE Department, RIET, Abohar, Punjab, India ³Professor, ECE Department, SLIET, Longowal, Punjab, India Abstract The design and development of microstrip patch antenna incorporation with fractal defected ground structure (FDGS) for emergency management is presented in this paper. The challenge behind the design of the antenna is to make it function over the bands of interest with wider bandwidth required for emergency management. The key dimensional parameters of the presented antenna have been optimized extensively using multiple simulations. The well-known methodology of utilizing DGS to enhance the bandwidth and to increase the number of frequency band has been efficiently utilized and examined critically. The obtained results reveal that proposed antenna possesses dual band (406.1-505.1 MHz and 604.0-837.4 MHz) and provide better impedance matching with wider bandwidth in comparison to the reference antenna (without DGS). Keywords Bandwidth; DGS; Emergency Management; Fractal; Slot; I. INTRODUCTION With the growing progress of wireless communication systems, the demand of low profile, low cost and wide band antennas is increasing day by day [1]. The microstrip patch antenna may be the better option for this requirement. It is always a great challenge in front of the antenna system design engineers to develop an efficient microstrip patch antenna that possesses broader bandwidth at user defined frequencies. In the literature several attempts has been made so far to overcome this limitation like application of slots on the patch [2, 3], coplanar waveguide (CPW) feed [4], partial ground plane [5], asymmetrical ground plane [6], defects in the ground plane [7]. However, there are many advantages of these techniques; still there is a scope of improvement in some of the performance parameters of the antennas. In this context, sincere efforts have been made in this paper to develop microstrip antenna incorporation with rectangular slot and fractal defected ground structure. This approach has been rarely used in the published work and provides significant results for the antenna design. The presented antenna has been designed and tuned for emergency management. An essential element for emergency management system is a faithful communication infrastructure that enables the rescue team to support for the collection and detailing of informative data approaching from different monitoring instruments spread in the area of disaster [8, 9]. II. DESIGN CONSIDERATION Fig. 1 shows the design of proposed antenna. The basic structure of the antenna is a simple rectangular patch that has been etched on the FR4 substrate having dielectric constant of 4.4 and loss tangent of 0.019. The height of the substrate is 1.6 mm. Further a rectangular slot in the center of the patch is taken out. The slot provided on the patch is accountable for miniaturization. In the similar manner, a square Koch curve fractal defect has been generated on the ground plane to explore the possibilities of broader bandwidth and multiband behavior. The finite dimension of the ground plane is characterized by length L1 and width W1. In order to design the antenna for emergency management, the dimensional parameters have been estimated using equations (1) & (2) [1]. Further critical optimization process has been performed to tune the proposed antenna for bands of interest such as 406.1 430 MHz, 440 www.ijaetmas.com Page 20
470 MHz, 746 806 MHz, 806 824 MHz and 851 869 MHz. The optimal dimensional parameters of the proposed antenna are detailed in Table I. ε eff = (εr+1) + (εr 1) 1 (1) 2 2 Z o = 1+12h/w 120 π εeff w h +1.393+0.667 ln w h +1.444 forw h 1 (2) (a) (b) (c) Fig.1 Geometry of the proposed antenna (a) top view of simple rectangular patch (b) patch with rectangular slot (c) bottom view of patch with square Koch curve shaped fractal DGS TABLE I DIMENSIONAL PARAMETERS OF THE PROPOSED ANTENNA Dimensional Parameters Length of Ground Plane, L 1 Width of Ground Plane, W 1 Length of Patch, L 2 Width of Patch, W 2 Length of Slot, L 3 Width of Slot, W 3 Length of Feed Strip, L 4 Width of Feed Strip, W 4 Length of DGS, L 5 Width of DGS, W 5 Values 118 mm 98.5 mm 97.2 mm 80.1 mm 40.3 mm 19.6 mm 9.4 mm 10.1 mm 15.3 mm 2.1 mm www.ijaetmas.com Page 21
III. RESULTS AND DISCUSSION The proposed antenna has been designed and simulated with full wave IE3D electromagnetic (EM) simulator. The IE3D simulator is built with the methodology of methods of moments. The corresponding results obtained from the simulator demonstrate that the simple rectangular patch resonates at 742.9 MHz with reflection coefficient of -23.84 db as shown in Fig. 2(a). In order to reduce the size of the proposed antenna, a symmetrical rectangular slot has been taken out from the center of the patch. The results of the proposed antenna with slot are plotted and overlap with the results of simple patch antenna, as shown in Fig. 2(b). It may be observed that by employing rectangular slot, the resonant frequency move towards lower side which is accountable for miniaturization of the proposed antenna. Further a square Koch curve shaped defect has been etched on the ground plane to enhance the bandwidth of the proposed antenna. The simulated results of scattering parameters of the proposed antenna with fractal DGS and rectangular slot is shown in Fig. 2(c). The investigation is done for the bands of interest required for emergency management. The incorporation of FDGS has not only been provided additional frequency band (from 406.1 MHz to 505.1 MHz) but also improve the impedance bandwidth and impedance matching to the considerable level. The input impedance of the proposed antenna with rectangular slot and FDGS is shown in Fig. 3. The resonant performance of the proposed antenna is detailed in Table II. (a ) (b) (c) Fig. 2 S 11 parameters of the proposed antenna for (a) simple patch (b) patch with rectangular slot (c) patch with slot and FDGS www.ijaetmas.com Page 22
(a) (b) Fig. 3 Input Impedance of the proposed antenna with rectangular slot and FDGS (a) Real part (b) Imaginary part TABLE II RESONATING PARAMETERS OF THE PROPOSED ANTENNA Parameters Resonating Frequency (MHz) Reflection Coefficient (db) VSWR Input Impedance (ohm) Bandwidth Patch 742.9-23.84 1.137 56.34-j2.551 29.93% Patch with Slot 731.3-22.58 1.162 58.09-j0.720 29.71% Patch with Slot & 434.3-23.20 1.149 43.57-j0.759 20.14% FDGS 752.5-20.49 1.209 42.16-j3.796 32.81% IV. RADIATION PATTERNS Fig. 4 shows the radiation patterns of the presented antenna in two principle planes, E- plane and H-plane at the resonant frequencies, 434.3 MHz and 752.5 MHz. It may be easily notice that the patterns in E-plane is more like of patterns of any dipole antenna having shape of 8 whereas the radiation patterns in H-plane is omnidirectional. www.ijaetmas.com Page 23
(a) Fig. 4 Radiation patterns of the proposed antenna (a) E-plane (b) H-plane (b) V. CONCLUSIONS In this paper, a rectangular patch has been taken as candidate structure to analyze the effect of rectangular slot and fractal defect on the resonating properties of the proposed antenna. The obtained results illustrate that by incorporation of FDGS and slot simultaneously, a significant improvement in the bandwidth and input impedance can be achieved. Moreover, the dimensional parameters of the antenna has been tuned for required frequency bands like 406.1 430 MHz, 440 470 MHz, 746 806 MHz, 806 824 MHz and 851 869 MHz that cover most of the frequency bands which make the antenna suitable for emergency management. ACKNOWLEDGMENT The authors are thankful to IKG Punjab Technical University, Jalandhar, Punjab, India to allow for carrying out this work and the ECE Department, SLIET Longwal, Sangrur, Punjab, India for providing valuable support. www.ijaetmas.com Page 24
REFERENCES [1] C. A. Balanis, Antenna Theory. John Wiley & Sons, Inc., Singapore, pp. 1-941, 1997. [2] H. Wong, K. K. So and X. Gao, Bandwidth enhancement of a monopolar patch antenna with V-Shaped slot for Car-to-Car and WLAN communications, IEEE Transactions on Vehicular Technology, Vol. 65, no. 3, pp. 1130 1136, Mar. 2016. [3] M. A Saed, Broadband CPW-Fed planar slot antennas with various tuning stubs, Progress In Electromagnetics Research, Vol. 66, pp. 199-212, 2006. [4] Y. Jee and Y. M. Seo, Triple Band CPW fed Compact Monopole Antennas for GSM/PCS/DCS/WCDMA Applications, Electronic Letters, vol. 45, no. 9, pp. 446-448, 2009. [5] S. Rani and A. P. Singh, A novel design of hybrid fractal antenna using BFO, Journal of Intelligent and Fuzzy Systems, Vol. 27, no. 3, pp. 1233-41, 2014. [6] S. Rani and A. P. Singh, Modified Koch fractal antenna with asymmetrical ground plane for multi and UWB applications, International Journal of Applied Electromagnetics and Mechanics, vol. 42, pp. 259-267, 2013. [7] S. Rani and A. P. Singh, Fractal antenna with defected ground structure for telemedicine applications, International Journal on Communications, Antenna and Propagation, Vol. 2, no. 1, pp. 6-9, Feb. 2012. [8] A. Lizzi, R. Azaro, G. Oliveri and A. Massa, Multiband fractal antenna for wireless communication systems for emergency management, Journal of Electromagnetic Waves and Applications; Vol. 26, no. 1, pp. 1-11, Apr. 2012. [9] S. Kakkar, T. S. Kamal and A. P. Singh, Small patch antenna with DGS for emergency management, Proc. MATEC Web Conferences Journal, Vol. 57, no. 01001, pp. 1-3, Jul. 2016. www.ijaetmas.com Page 25