Design and Analysis of I-Shaped Microstrip Patch Antenna For Low Frequency

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1 IJIRST International Journal for Innovative Research in Science & Technology Volume 1 Issue 6 November 2014 ISSN (online): Design and Analysis of I-Shaped Microstrip Patch Antenna For Low Frequency Shivani Chourasia PG Student Lakshmi Narain College of Technology & Science Bhopal (M.P.) Dr. Soni Changlani Professor Lakshmi Narain College of Technology & Science, Bhopal (M.P.) Pooja Gupta Assistant Professor Lakshmi Narain College of Technology & Science Bhopal (M.P.) Abstract Microstrip patch antennas are the popular antennas due to their low profile, conformable, easy, inexpensive, and versatile in terms of realization and are thus been widely used in a various useful applications. In this paper, an I-shaped microstrip patch antenna is being designed for L-band with an operating frequency of 1.5 GHz using the substrate material Flame Retardant 4, FR-4 lossy having the dielectric constant of 4.3. The parameters such as return loss, efficiency and directivity of the design are simulated and analyzed using Computer Simulation Technology (CST) Microwave Studio. Keywords: I-Shaped Microstrip Patch Antenna (ISMPA), CST Software, FR-4 Substrate, Patch Length, Patch Width. I. INTRODUCTION A microstrip antenna constitutes of a very thin metallic patch placed on conducting ground plane, separated by a dielectric substrate [2]. A patch antenna consists of a radiating patch that may be square, circle, triangle, ring and rectangle etc. on one side of a dielectric material substrate and a ground plane on the other side of it. Microstrip antennas are very popular and thus preferred due to their numerous advantages such as lightweight, low profile, easy, inexpensive fabrication and simple modeling. They are very versatile when chosen with a particular patch shape in terms of polarization, pattern and resonant frequency and easily combine to form linear or planar arrays [1]. They have different feeding techniques like microstrip line feed, coaxial probe feed, aperture coupling feed, and proximity coupling feed [4-5]. Recently, it was necessary to minimize the size of antenna due of tremendous development in the field of wireless communication systems. However, many limitations are there because the size of antenna increases proportional to wavelength. The proposed work includes an I-shaped radiating patch design designed for 1.5 GHz frequency made by using microstrip line feed and simulated by CST 10 software. The design was made keeping in mind the miniaturization of size. The antenna is designed for L-band which has a wide range of applications. The operating frequency range used falls under UHF frequency range. A typical microstrip patch antenna is shown in Fig.1. Fig. 1: Microstrip Patch Antenna II. DESIGN METHODOLOGY Microstrip patch antennas consist of a very thin metallic strip placed over a substrate above the ground plane. There are various substrates that can be used for the designing of patch antennas, and their dielectric constant ε r is usually in the range of 2.2 ε r 12 [1]. The dielectric constant used for microstrip antenna is kept generally low in the lower end of the range to reduce fringing All rights reserved by 320

2 field but for less critical applications [7]. Also, variation in dielectric constant for substrate is used for impedance matching [8]. It provides better efficiency, larger bandwidth, loosely bound fields for radiation into space. The patch can be made up of conducting material such as copper and gold. A. Feed Selection: A feed line is used to excite the radiator by direct or indirect contact [6]. In this work, among the four feeding techniques microstrip line feed is applied due to its advantage that it is easy to fabricate, simple to match by controlling the inset position and rather simple to model. A patch is added to the radiating patch using boolean addition option in CST software. On simulating the design for various feed lengths and widths, it was observed that the feed can be placed at any place within the patch length to match with its input impedance usually 50 ohm as the difference in the values of the parameters is negligible [9]. A microstrip line feed in an I-shaped patch antenna is shown in Fig.2. Fig. 2: Microstrip Line Feed B. Antenna Design Equations: The formulas to determine the I-shaped patch are given below, W = (1) ε reff = = ( ) ( ) (2) (3) L = 2ΔL (4) where, ε r = dielectric constant of the substrate, ε reff = effective dielectric constant, f r = resonant frequency, h = height of the substrate, L = actual length & W = width of the patch. From these equations, we can easily obtain the length & width of the design as desired and proceed with simulation. III. MODELING AND DESIGNING OF I-SHAPED PATCH ANTENNA The conducting patch can take any shape like square, rectangular, dipole, circular, elliptical, triangular, or any other configuration. The popular among all are rectangular, circular because of the ease of analysis and fabrication, and their attractive radiation characteristics, especially low cross-polarization radiation [1]. In this paper, we have taken I-shape as radiating patch design. Simulation was done using CST 10 software. The analysis was made on the basis of maximum return loss in db and efficiency in percentage. Design is influenced with the idea of miniaturization and is designed on a finite dielectric substrate placed over a ground plane. The substrate thickness was kept h = 1.6 mm while the width and length of the ground plane and substrate was 50mm [10-11]. The substrate material used was FR-4 lossy with dielectric constant ε r = 4.3 which is less expensive for fabrication [11-12]. All rights reserved by 321

3 These values were kept constant throughout the work. An I-shaped patch was designed over the substrate by cutting slots on both the sides of reference axis from a rectangular patch and at one of the branch of I-shaped antenna microstrip line feed was given using tools available in CST 10. Feed was given at the lower edge of the patch. The design was simulated over a frequency range of 0 3 GHz. Length & width of the slot and width of the feed line patch were varied. The desired results were obtained with patch length L = 4.6 mm & W = mm. A perspective view of I-shaped microstrip patch antenna is shown in Fig.3. Fig. 3: 3D View of ISMPA In CST Environment IV. RESULT After the simulation of I-shaped patch antenna in the CST environment, it was found that the designed patch antenna was obtained with maximum return loss = db at the desired frequency 1.5 GHz. Also, the size of the patch was 60 x 70 mm. The return loss graph is shown in Fig.4. Also, the polar plot and radiation pattern of the design is shown in Fig.5 and Fig.6. Fig. 4: Graph Showing Simulated Response For ISMPA Fig. 5: Polar Plot of ISMPA All rights reserved by 322

4 Fig. 6: Radiation Pattern of ISMPA The return loss obtained for ISMPA was above -10 db that is the minimum criteria for evaluating the performance any patch antenna. The performance parameters of the ISMPA are shown in table 1 below. Table - 1 Performance Parameters S.No. Parameters ISMPA 1. Frequency 1.5 GHz 2. Patch Size Length = 4.6 mm & Width = mm 3. Return loss db 4. Efficiency db V. CONCLUSION From the above results, we can say that for miniaturization at 1.5 GHz that has wide applications in military telemetry, GPS, mobile phones GSM (Global System for Mobile Communication) and amateur radio, I-shaped microstrip patch antenna provides the best results in terms of return loss. The simulated antenna using FR-4 lossy material as substrate with microstrip line feeding technique in CST 2010 software is shown in Fig.4. ACKNOWLEDGMENT I am highly grateful to Pooja Gupta, Assistant Professor at LNCTS for giving me invaluable guidance in this field and providing me the opportunity to carry out this work further. I also present my gratitude to Dr. Soni Changlani, Professor at LNCTS. It was their essential encouragement that enabled me to pursue my work in this field. REFERENCES [1] Antenna Theory, C. Balanis, Wiley, 2nd edition (1997), Chapter 14.ISBN [2] Mamta Devi Sharma, Abhishek Katariya, Dr. R. S. Meena, E Shaped Patch Microstrip Antenna for WLAN Application Using Probe Feed and Aperture Feed,International Conference on Communication Systems and Network Technologies [3] N. Ripin, S. N. C. Yusoff, A. A. Sulaiman, N. E. A. Rashid and M. F. Hussin, Enhancement of bandwidth through I-Shaped Defected Ground Structure, IEEE International RF and Microwave Conference (RFM 2013), December 09-11, [4] J. R. James and P. S. Hall, Handbook of Microstrip Antennas, Vols. 1 and 2, Peter Peregrinus, London, UK, [5] R. E. Munson, Microstrip Antennas, Chapter 7 in Antenna Engineering Handbook (R. C. Johnson and H. Jasik, eds.), McGraw-Hill Book Co., New York, [6] A. Vishwapriya, S. Banu, R. Yogamatthi, Design and analysis of I-shaped MIMO antenna for wireless applications, Computing, Communications and Networking Technologies (ICCCNT), 4th International Conference, [7] D. M. Pozar, Microstrip Antennas, Proc. IEEE, Vol. 80, No. 1, pp , January [8] Prasanna L. Zade, Sachin S. Khade, Dr. N. K. Choudhary, Modeling and Designing of Circular Microstrip Antenna for wireless communication Second International Conference on Emerging Trends in Engineering and Technology, All rights reserved by 323

5 [9] M.M. Sharma, N. C. Bajia, Vinita Agarwal, Shilpi Kumawat, Swati Gupta and R.P. Yadav, Compact Microstrip Circular Patch Antenna for Wi-max with Double-layered Substrate, International Conference on Microwave 08, [10] Subodh Kumar Tripathi, Vinay Kumar, E-Shaped Slotted Microstrip Antenna with Enhanced Gain for Wireless communication, International Journal of Engineering Trends and Technology - July to Aug Issue [11] P. K. Singhal, B. Garg, and N. Agrawal, A High Gain Rectangular Microstrip Patch Antenna Using Different C Patterns Metamaterial Design in L- Band, Advanced Computational Techniques in Electromagnetics, vol. 2012, pp. 1 5, [12] Sohag Kumar Saha, Amirul Islam Rony, Ummay Habiba Suma, Md. Masudur Rahman, E-Shape microstrip patch antenna design for wireless applications, International Journal of Science, Engineering and Technology Research (IJSETR) Volume 2, Issue 3, March All rights reserved by 324