2014 IEEE Students’ Conference on Electrical, Electronics and Computer Science

978-1-4799-2526-1/14/$31.00 ©2014 IEEE

Multiple T Slot Compact & Ultra Wide Band Microstrip Patch Antenna for Wimax Applications Rajan Mishra1, Nitin Muchhal2, Ravi Shankar Mishra3

M.Tech Final year Student1, Associate Professor2, Professor & Head3

Department of ECE Sagar Institute of Science and Technology SISTec, Bhopal India

Abstract: In this paper, a compact Microstrip patch antenna having a slit associated with the slot for WiMAX application is presented. Instead of semi-infinite ground plane, the proposed antenna adopts the partial ground plane. Radiating patch lies on the Glass epoxy PCB substrate which is having low dielectric constant, thereby provides good bandwidth. Microstrip feedline technique is used to feed the antenna with 50Ω impedance. WiMAX (Worldwide Interoperability for Microwave Access) has three frequency bands- the lower band (2.5-2.69 GHz), the middle band (3.2-3.6 GHz), and the upper band (5.2-5.8 GHz). This proposed antenna enhances the return loss to -22.25 dB at the middle frequency range of WiMAX application. Computer simulated results showing the VSWR <2 in the middle frequency range of WiMAX. The antenna is fed by a coaxial probe feed. The antenna designs and performances are analyzed using Zealand IE3D software. The antenna can be used for many modern communication systems. The bandwidths of the middle frequencies band are 26.5% & the return loss S11 characteristic is -22.24 dB. Keywords: - Slotted Patch Antenna, Ultra Wide Band, Wimax, Compact Antenna

I INTRODUCTION

Wireless Communication [1] has been developed widely and rapidly in the modern world especially during the last two decades. The future development of the personnel communication devices will aim to provide image, speech and data communication at any time, and anywhere around the world. This indicates that future communication terminal antenna must meet the requirements of wideband to sufficiently cover the possible operating band. . The IEEE 802.16 working group has established a new standard known as WiMAX (Worldwide Interoperability for Microwave Access) [4] which can reach a theoretical up to 30-mile radius coverage. Moreover, in the case of WiMAX, the highest theoretically achievable transmission rates are

possible at 70 Mbps. One of the potential applications of WiMAX is to provide backhaul support for mobile WiFi hotspots. Researchers are focusing on how to design antennas for WiMax technology. WiMax has three allocated frequency bands, the low band (2. 5-2.69 GHz), the middle band (3.2-3.8 GHz) and the upper band (5.25.8 GHz). Due to its advantages such as low-cost, small size low weight and capability to integrate with Microwave integrated circuits, the microstrip patch antenna [2], [3] is a very good candidate for integrations in applications such as wireless communication systems, mobile phones and laptops. This paper describes a multiple T slot microstrip antenna is designed and simulated for achieving the compact and ultra wide band WiMax middle band as Ultra wideband (UWB) systems are attracting more and more attentions in a wide range of applications. Miniature antennas are also well desired for wireless communications systems. Therefore as bandwidth enhancement and size reduction are becoming major design considerations for practical applications and our design meet both the criteria with better efficiency.

Various methods have been employed for the bandwidth enhancement of Microstrip patch antenna viz. Multilayer patch [5 ], Stacked antenna [7 ], use of impedance match Network [6], use of meta-materials [11] & Slotted antenna etc. Amongst them slotted antennas are most preferred one and in past various shapes [ 8 ], [9 ], [10 ] have been explored for wireless applications. A Multi U-slot patch antenna has been reported recently for GSM application [12]. In the present paper, we have used multiple T slots for achieving Ultra wideband for Wimax application with compact size of antenna.

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II. DESIGN FORMULAS AND PROCEDURE A tradeoff off relationship exists between antenna size and bandwidth [4]. Generally, the relationship of width and height and relative dielectric constant of substrate are related as:

121 1 1 12

2 2r r

reffhw

ε εε−+ − ⎡ ⎤= + +⎢ ⎥⎣ ⎦

Substrate thickness should be chosen as large as possible to maximize bandwidth, but not so large to minimize the risk of surface wave excitation. The substrate should also have low dielectric constant in order to achieve high efficiency. Since the effective length of the patch has been extended by ¨L on each side, the effective length of the patch is expressed as

reffL L L= + Δ

After analyzing and determining the physical nature of the Micro-strip antenna with reference of resonant frequency fr , relative dielectric constant, εr , height of the substrate h is:

22 1r

cwf ε

=+

The actual length (L) of Patch is obtained by

L = Leff – 2ΔL

III. ANTENNA DESIGN

Fig. 1 shows the proposed probe-fed multiple T slotted patch antenna. In this design pairs of symmetrical T crossed slots are etched out— from the two halves of the surface. The proposed antenna is design by cutting total six symmetrical slots of unequal sizes in rectangular patch to make it a multiple T shaped antenna as shown in fig 1. Cutting of these slots in antenna increases the current path which increases current intensity as a result bandwidth and efficiency is increased. The substrate dielectric material is Glass Epoxy PCB with dielectric constant 4.2. The substrate thickness is 1.6mm and loss tangent is 0.019. The dimension of the ground plane is taken as (70mmx70mm) and the total bandwidth achieved is 28.5% for VSWR< 2 and efficiency is nearly 78%.

The essential parameters for the design of a T slot rectangular micro-strip Patch Antenna are: Length (L): The two sides are selected to be of equal length & 21.95 mm each. Width (W): The two sides are selected to be of equal length and 28.7mm each. Dielectric constant of the substrates (εr): 4.3 with height 1.6mm. Slot Length along the X axis (Ws): The length of both slots along the X axis was adjusted to be 6mm in order to obtain better results. Slot width along the Y axis (Ls): The width of both slots along the Y axis was adjusted to be 19 mm in order to obtain better results. Slot Width (w): The width of both the slots at the tail part was adjusted to be 6mm to obtain better results. Slot Width (l): The length of both the slots at the tail part was adjusted to be 23mm to obtain better results.

Fig 1 Simulated Geometry of Multiple

Fig 2. 3D View of designed antenna

Fig 3 Fabricate Antenna front vie

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e T-slot Antenna

ew

Fig 4 Fabricate Antenna b

IV RESULT AND DIS

The proposed antenna is simSimulator IE3D[15] and variousLoss, Gain, VSWR etc) are mshows the S11 parameters bandwidth) for the proposed antantenna resonates nearly at Wim3.2 GHz. The return loss for 3.2which covers the minimum requloss of -10 dB with approxim26.50%. The following parameteS11, VSWR, Gain, Directivity, Rare observed and found to be witapplication of antenna for desired

Fig 5. Return Loss

back view

CUSSION

mulated using EM parameters (Return measured. Figure 3

(return loss and tenna. The designed max middle band of 2 GHz is -22.24 dB uired value of return mate bandwidth of ers[13], [14] namely

Radiation Pattern etc thing limit for better

d application.

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Fig 6 . VSWR plot

Fig 7 Efficiency Vs Frequency

Fig 8. Directivity of 6 dbi

Fig. 9 Smith Chart

Fig. 10 Radiation Pattern

Fig. 11 Current Distribution

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Fig. 12 Polar Elevation Pattern

V CONCLUSION

The aim of this project is to design a rectangular multilayer patch Microstrip antenna and to study the responses and the radiation properties of the same. Multilayer Micro-strip patch is also useful to provide protection to patch from heat, rain, physical damage, and naturally formed ice layers during flight. Further Antenna dimension shows the compactness of the design with a dielectric constant of 4.3(FR4), which has a loss tangent of 0.019 at 3.22GHz. The result shows Ultra wide bandwidth at 3.2 GHz which is 1.65GHz (26.5%) with high return loss of -22.24dB. This antenna has a very simple structure printed on a very cheap FR4 substrate for commercial purposes. Wideband has been achieved by using multiple slots on the patch. The work can be further extended by introducing shorting pins and stacked patch configuration to include more bands and cover other bands of Wimax & WLAN applications.

. REFERENCES

[1] Mobile Communications Engineering, C. Y Lee ,2/e McGraw-Hill 2001 [2] “K.L Wong Compact and Broadband Microstrip Antennas”, John Wiley & Sons, Inc, 1992 [3] Broadband Microstrip Antennas”, Girish Kumar, K.P Roy, Artech House 2003

[4] P. Pigin, “Emerging mobile WiMax antenna technologies”, IET Communication Engineer, October/ November 2006

[5] Inclan-Sanchez, L , Gain & Bandwidth Enhancement of a Multilayer Microstrip patch antenna by means of a truncated planar periodic structure” 3rd European Conference on Antennas and Propagation, EuCAP, Berlin 23-27 March 2009, Page(s): 3206 - 3209 [6] Pues, H.F, Van de Capelle, A.R “An impedance-matching technique for increasing the bandwidth of Microstrip”, IEEE Transactions on Antennas and Propagation, Volume:37 , Issue: 11, Page(s):1345 – 1354. [7] Trivedi, R.D, Dwivedi V.”Stacked Microstrip Patch Antenna: Gain and Bandwidth Improvement” International Conference on Communication Systems and Network Technologies (CSNT), Rajkot 11-13 May 2012, Page(s):45 - 48 [8] Archevapanich, T., Anantrasirichai, N,” Inversed E-Shape slot antenna for WLAN applications” IEEE International Conference on Control, & Automation ICCAS 2007, Seoul

[9] Latif, S.I, Shafai, L.”Wideband and reduced size Micro strip L-slot antennas for wireless applications”, IEEE Antennas and Propagation Society, 20-25 June 2004 Vol.2, Page(s): 1959 - 1962 .

[10] J. S. Roy and M. T. Themal, "Design of a circularly polarized Microstrip antenna for WLAN," Progress In Electromagnetics Research M, Vol. 3, 79-90, 2008.

[11] Han Xiong, Yue-Hong Peng ”Impedance Bandwidth and Gain Improvement for Microstrip Antenna Using Metamaterials “,Microwave and Optical Technology Letters, Volume 55, Issue 4, pages 786–789, April 2013

[12] Nitin Muchhal, Md Nawaz Ahmed,” A Novel Planar U Slotted Micro Strip Patch for GSM (1.8 GHz Band) Applications” National Conference on Broad Band Communication & Technologies (NCBBCT), MANIT Bhopal, 22 – 23 August 2013 [13] D. M. Pozar, Microwave Engineering. New York: Addison-Wesley, 1990, p. 185. [14] C. A. Balanis, Antenna Theory: Analysis and Design. New York: Wiley, 1997, p. 734. [15] IE3D user manual About the Authors Rajan Mishra is presently pursuing M.tech(digital Communication) from Sagar Institute of Science and Technology (SISTec),Bhopal India affiliated to RGTU. He obtained his B.E.(ECE) from NRI IIST Bhopal . His research interests include Patch antenna design, and modelling of Microwave and RF Components. Nitin Muchhal is presently working as an Associate Professor in ECE department of SISTec, Bhopal. He has obtained his B.E. (ECE) from BIT, Mesra and M.Tech (Microwave Electronics) from University of Delhi (UDSC), New Delhi India. He has 8 years of industrial and

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teaching experience. His research interests include Patch antenna design, Microwave, Wireless Sensors, Digital and Mobile communication. He has published/presented 16 papers in national and international journals/conferences. He is a member of IEEE, MSI and IE (I). He is also acting as Branch counsellor of IEEE student branch at SISTec Bhopal (India).

Dr. Ravi Shankar Mishra received his Ph.D. and M.Tech. from M.A.N.I.T. Bhopal and his PG diploma in VLSI design from C-DAC Bangalore. He has teaching and research experience for more than 13 years. Presently, he is working as a professor and head in the Department of Electronics and Communication Engineering at Sagar Institute of Science and Technology (SISTec), Bhopal, India. He has had more than 30 research papers published in reputed international journals and/or presented at conferences, including SPIE, he is also reviewer of many journals. His areas of interests are optical communication, digital signal processing, computer communication and Microstrip patch antenna and guided several M.Tech thesis in these areas. He is a Life Fellow Member of the Institution of Electronics & Telecommunication Engineers (IETE).