Enhanced bandwidth slotted microstrip patch antenna

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  • 1. INTERNATIONAL JOURNAL OF ELECTRONICS AND International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN 0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 2, March – April (2013), © IAEMECOMMUNICATION ENGINEERING & TECHNOLOGY (IJECET)ISSN 0976 – 6464(Print)ISSN 0976 – 6472(Online)Volume 4, Issue 2, March – April, 2013, pp. 41-47 IJECET© IAEME: www.iaeme.com/ijecet.aspJournal Impact Factor (2013): 5.8896 (Calculated by GISI) ©IAEMEwww.jifactor.com ENHANCED BANDWIDTH SLOTTED MICROSTRIP PATCH ANTENNA Anurag Sharma*, Ramesh Bharti**, ArchanaAgarwal*** *M-Tech Student, Jagannath University, Jaipur **Assistant Professor, Jagannath University, Jaipur ***Assistant Professor, Institute of Technology and Management, Bhilwara ABSTRACT In this paper, in order to improve the performance of a conventional microstrip patch antenna a new design technique for enhancing the bandwidth of antenna is proposed. This paper includes a wideband inverted slotted microstrip patch antenna fed by microstrip transmission line feed. The design enumerates contemporary techniques such as microstrip transmission line feeding, inverted patch structure and slotted patch. The combined effect of integrating these techniques and by introducing the proposed design, offer a low profile, enhanced bandwidth, and high gain. The antenna operating the band of 1-12 GHz shows an impedance bandwidth (2:1 VSWR) of UWB. Keywords: Slotted antenna, Microstrip patch antenna, wideband, Microstrip Transmission Line fed. I. INTRODUCTION As the process of miniaturization of devices is in full swing, antennas cannot remain as standalone devices. Compact designs have to be implemented to cope with the demands of the industry. With the explosive growth of wireless system and booming demand for a variety of new wireless application, there is great need to design broadband antennas to cover a wide frequency range. Now days the designers are basically focused to deal with UWB (Ultra Wide Band) Technology and to make advance antennas that can give UWB response so that they can be operated in that particular frequency range. With increasing requirements for personal and mobile communications, the demand for smaller and low-profile antennas has 41
  • 2. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 2, March – April (2013), © IAEMEbrought the microstrip antennas to forefront. Modifying the shape and dimensions ofconventional microstrip antennas leads to the design of microstrip antenna for UWBcommunication system by tuning the shape and dimensions. Present time is witnessing a veryrapid growth of wireless communications, for which antennas with very large bandwidth arein strong demand. Microstrip antennas are attractive due to their light weight, conformabilityand low cost and have broad application in wireless communication system owing to theiradvantages such as low-profile, conformability, low-cost fabrication and ease of integrationwith feed-networks [7]. For good antenna performance, a thick dielectric substrate having alow dielectric constant is desirable since this provides better efficiency, larger bandwidth andbetter radiation. However, such a configuration leads to a larger antenna size. In order todesign a compact Microstrip patch antenna, substrates with higher dielectric constants mustbe used which are less efficient and result in narrower bandwidth. Hence a trade-off must berealized between the antenna dimensions and antenna performance. There are variousmethods to increase the bandwidth of antennas, including increase of the substrate thickness,the use of a low dielectric substrate, the use of various impedance matching and feedingtechniques, the use of multiple resonators, and the use of slot antenna geometry[2],[5],[6]. In order to enhance the bandwidth, several techniques have been proposed. A novelsingle layer wide-band rectangular patch antenna with achievable impedance bandwidth ofgreater than 20% has been demonstrated [3]. Utilizing the shorting pins or shorting walls onthe unequal arms of a U-shaped patch, U-slot patch, or L-probe feed patch antennas,wideband and dual-band impedance bandwidth have been achieved with electrically smallsize [4],[9],[10]. In this paper, for enhancing the impedance bandwidth, a novel slotteddouble E shape patch is proposed. A better cross-polarization and wider impedancebandwidth of 28% is achieved compared to the design reported in [11].II. ULTRA-WIDE BAND TECHNOLOGY UWB or Ultra-Wide Band technology offers many advantages, especially in terms ofvery high data transmission rates which are well beyond those possible with currentlydeployed technologies such as 802.11a, b, g, WiMax and the like. As such UWB, ultrawideband technology is gaining considerable acceptance and being proposed for use in anumber of areas. Already Bluetooth, Wireless USB and others are developing solutions, andin these areas alone its use should be colossal. Just as many wireless technologies seem to be moving into high volume productionand becoming established a new technology has hit the scene and is threatening to turn theindustry upside down. Known as Ultra Wide Band (UWB) this new technology has much tooffer both in the performance and data rates as well as the wide number of application inwhich it can be used. Currently ultra wideband (UWB) technology has been proposed for oris being used in applications from radar and sensing applications right through to high bandwidth communications. Furthermore ultra wide band, UWB can be used in both commercialand military applications. There are a wide number of applications that UWB technology can be used for. Theyrange from data and voice communications through to radar and tagging. With the growingnumber of way in which wireless technology can be used, the list is likely to grow. Due to theextremely low emission levels currently allowed by regulatory agencies, UWB systems tendto be short-range and indoors. However, due to the short duration of the UWB pulses, it iseasier to engineer extremely high data rates. 42
  • 3. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 2, March – April (2013), © IAEME Fig 1. Comparison of Narrowband, Spread Spectrum and Ultra wide band Signal Concept With the growing level of wireless communications, ultra wide band UWB offerssignificant advantages in many areas. One of the main attractions for WAN / LANapplications is the very high data rates that can be supported. With computer technologyrequiring ever increasing amounts of data to be transported, it is likely that standards such as802.11 and others may not be able to support the data speeds required in some applications. Itis in overcoming this problem where UWB may well become a major technology of thefuture. Fig 2. Features and benefits of UWBIII. DESIGN PROCEDURE The basic design steps includes following parameters Frequency of operation: Theresonant frequency must be selected appropriately. For my design the frequency selected willbe from ultra wideband frequency range. Dielectric constant of the substrate εr: The Dielectric constant of the substrate plays animportant role in patch antenna design. A substrate with high dielectric constant reduces thedimensions of antenna but it also affects the antenna performance. So, there is a trade-offbetween size and dimensions of antenna.Height of Dielectric substrate: For the Micro strip patch antenna to be used in communicationsystem, it is essential that the antenna is not bulky. Hence the height of dielectric should beless. 43
  • 4. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 2, March – April (2013), © IAEMEIV. ANTENNA DESIGN LAYOUT Fig. 3 depicts the geometry of the proposed patch antenna. The inverted rectangularpatch, with width W and length L is supported by a low dielectric superstrate with dielectricpermittivity εl and thickness hl. An air-filled substrate with dielectric permittivity εo andthickness ho is sandwiched between the superstrate and a ground plane. The proposed patchintegrates the double E shaped patch on the same radiating element. For the main E-shaped,the slots are embedded in parallel on the radiating edge of the patch symmetrically withrespect to the centerline (x-axis) of the patch and it is incorporated extra E shaped slot on thesame radiating edge of opposite side. The patch is fed by a coaxial probe along the centerline(x-axis) at a distance H from the edge of the patch as shown in Fig. 1(b). Table I shows theoptimized design parameters obtained for the proposed patch antenna. A dielectric substratewith dielectric permittivity, εl of 2.2 and thickness, hl of 1.5748mm has been used in thisresearch. The thickness of the air-filled substrate ho is 12.5mm. An Aluminum plate withdimensions of 1.393 λ0 ×1.254 λ0 (where λ0 is the guided wavelength of the centre operatingfrequency) and thickness of 1 mm is used as the ground plane. The proposed antenna isdesigned to operate at 1.80 GHz to 2.36 GHz region. This design employs contemporary techniques namely, the microstrip transmissionline feeding, inverted patch, and slotted patch techniques to meet the design requirement. Theuse of transmission line feeding technique with a thick air-filled substrate provides thebandwidth enhancement, while the application of superstrate with inverted radiating patchoffers a gain enhancement, and the use of parallel slots also reduce the size of the patch. Theuse of superstrate on the other hand would also provide the necessary protections for thepatch from the environmental effects. By incorporating extra E shape slots in radiating edges,the gain and cross-polarization has been improved. These techniques offer easy patchfabrications, especially for array structures. Fig 3. Geometry of proposed patch antenna Dimension W L w0 l0 h0 H mm 75 46 7 30 12.5 12 Dimension w1 l1 hl Wf Lf Gpf mm 15 5 1.5748 6.2 35.1 1 Table 1 Proposed Patch antenna design parameters in millimeters (mm) 44
  • 5. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 2, March – April (2013), © IAEMEV. SIMULATION RESULTS CST Microwave Studio has been used to calculate return loss, impedance bandwidth,radiation pattern and gains. Fig. 4 and Fig.6 depicts the simulated result of the return loss andgroup delay of the proposed antenna. From the figure, the simulated group delay shows lessvariation on broader bandwidth except for sharp changes at the middle of the centerfrequency at 6.85 GHz. The simulated impedance bandwidth of 5 GHz is achieved at 10 dB return loss(VSWR≤2). Fig 4: Return Loss Curve of the proposed patch antenna Antenna radiation pattern depicts the radiation properties on antenna as a function ofspace coordinate. For a linearly polarized antenna, performance of antenna is often describedin terms of the E and H plane patterns [12]. The H-plane is defined as the plane containingthe magnetic field vector and the direction of maximum radiation [13] while E-plane as theplane containing the electric field vector and the directions of maximum radiation while Fig.5shows the simulated two dimensional E and H-plane at upper bound frequency. In the E-plane, the value of azimuth angle of 0o, 45o and 90o while in H-plane, the value of o o oelevation angle θ of 0 , 45 and 90 are taken into consideration. Fig 5: Radiation pattern curve of the proposed patch antenna 45
  • 6. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 2, March – April (2013), © IAEME Fig 6: Group delay of the optimized proposed antenna.VI. CONCLUSION For enhancing bandwidth of microstrip a new double E shaped patch antenna issuccessfully designed in this paper. An impedance bandwidth of 5 Ghz is achieved in thisdesign with respect to the centre frequency of 6.85 GHz by employing proposed slotted patchshaped design, inverted patch, and microstrip transmission line feeding techniques. With this,good radiation characteristics and antenna gain have also been obtained. The proposed patchhas a simple structure with dimension of 0.516 λ0× 0.383 λ0. The design is suitable for arrayapplications with respect to a given frequency of 1-12 GHz.REFERENCES[1] Norbahiah Misran, Mohammed N. Shakib, Mohammad T. Islam, and Baharudin Yatim ,“Design Analysis of a Slotted Microstrip Antenna for Wireless Communication,” WorldAcademy of Science, Engineering and Technology 49 2009.[2] K. L. Lau, K. M. Luk, and K. L. Lee,“Design of a circularly-polarized vertical patchantenna,” IEEE Trans. Antennas Propag., vol. 54, no. 4, pp. 1332-1335, 2006.[3] F. Yang, X. Zhang, Y. Rahmat-Samii, “Wide-band E-shaped patch antennas for wirelesscommunications,” IEEE Trans. Antennas Propag., vol. 49, pp. 1094-1100, 2001. [4] Y. X. Guo, K. M. Luk, K. F. Lee, and R. Chair, “A quarter-wave Ushaped antenna withtwo unequal arms for wideband and dual-frequency operation,” IEEE Trans. AntennasPropag., vol. 50, pp. 1082-1087, 2002.[5] D. M. Pozar and D. H. Schaubert, Microstrip antennas, the analysis and design ofMicrostrip antennas and arrays, New York: IEEE press, 1995.[6] D. M. B. Sun, I. S. Song, S. H. Choa, I. S. Koh, Y. S. Lee, and J. G. Yook, “Package-Level integrated antennas based on LTCC technology,” IEEE Trans. Antennas Propag., vol.54, no. 8, pp. 2190-2197, 2006.[7] W.He, R. Jin, and J. Geng, “E-Shape patch with wideband and circular polarization formillimeter-wave communication,” IEEE Trans. Antennas Propag., vol. 56, no. 3, pp. 893-895, 2008.[8] Y. P. Zhang and J. J. Wang, “Theory and analysis of differentiallydriven microstripantennas,” IEEE Trans. Antennas Propag., vol. 54, no. 4, pp. 1092-1099, 2006.[9] R. Chair, C. L. Mak, K. F. Lee, K. M. Luk, and A. A. Kishk, “Miniature wide-band halfU-slot and half E-shaped patch antennas,” IEEE Trans. Antennas Propag., vol. 53, pp. 2645-2652, 2005. 46
  • 7. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 2, March – April (2013), © IAEME[10] C. L. Mak, K. M. Luk, K. F. Lee, and Y. L. Chow, “Experimental study of a microstrippatch antenna with an L-shaped probe,” IEEE Trans.Antennas Propag., vol. AP-48, pp. 777–783, May 2000.[11] M. Tariqul Islam, N. Misran, and K. G. Ng, “A 4×1 L-probe fed Inverted Hybrid E-HMicrostrip Patch Antenna Array for 3G Application,” American J. Applied Sciences, vol. 4,pp. 897-901, 2007.[12] Hertz, H., Electrical Waves, London, Macmillan and Co., 1893.[13] Breed, G., “A summary ofF CC rules for ultra wideband communications,” HighFrequency Electronics, 42–44, Jan. 2005.[14] M. Veereshappa and Dr.S.N Mulgi, “Design And Development Of Triple BandOminidirectional Slotted Rectangular Microstrip Antenna” International journal ofElectronics and Communication Engineering &Technology (IJECET), Volume 3, Issue 1,2012, pp. 17 - 22, ISSN Print: 0976- 6464, ISSN Online: 0976 –6472.[15] Mahmoud Abdipour, Gholamreza Moradi and Reza Sarraf Shirazi, “A Design ProcedureFor Active Rectangular Microstrip Patch Antenna” International journal of Electronics andCommunication Engineering &Technology (IJECET), Volume 3, Issue 1, 2012,pp. 123 - 129, ISSN Print: 0976- 6464, ISSN Online: 0976 –6472.[16] K. Karuna Kumari and Dr. P.V.Sridevi, “Performance Evaluation of Circular MicrostripPatch Antenna Array with Different Dielectric Substrate Materials” International journal ofElectronics and Communication Engineering & Technology (IJECET), Volume 4, Issue 1,2013, pp. 236 - 249, ISSN Print: 0976- 6464, ISSN Online: 0976 –6472. 47