Bandwidth Enhancement of W Slot Microstrip Antenna using Stacked Configuration

Zakir Ali1, Vinod Kumar Singh1, Ashutosh Kumar Singh2, Shahanaz Ayub2

1I.E.T. Bundelkhand University, Jhansi 1S.R.Group of Institutions, Jhansi

2Indian Institute of Information Technology , Allahabad 2Bundelkhand Institute of Engg. & Technology, Jhansi

zakirali008@gmail.com , singhvinod34@gmail.com , ashutosh_singh@iiita.ac.in, shahanaz_ayub@rediffmail.com

Abstract: In this paper, bandwidth of microstrip antenna is increased by introducing a slot of W shape and using stacked configuration. The proposed W slot MSA is suitable for high speed WLANs applications. By using different approach of bandwidth enhancement such as stacked configuration, cutting slot and changing the position of the coaxial probe bandwidth equal to 25.78% is achieved. The antenna is fed by coaxial probe feeding technique. The designed antenna operates in the frequency range of 4.381GHz to 5.668GHz covering the WLAN frequency band of 5.15 GHz – 5.35 GHz. The antenna is designed using air as a dielectric substrate between the two layers and simulated on the Zeland IE3D software. Keywords: W Slot, Stacked, Wideband Antenna, and WLAN. I - INTRODUCTION The demand of microstrip antennas still persists due to its light weight, low profile, low cost and ease of integration with microwave circuit and no other antenna still could replace its features and hence it is being widely used in the wireless and other applications. However standard rectangular microstrip antenna has the drawback of narrow bandwidth and low gain. The bandwidth of microstrip antenna may be increased using number of techniques such as use of a thick or foam substrate , cutting slots or notches like U slot , E shaped , H shaped patch antenna, introducing the parasitic elements either in coplanar or stack configuration, and modifying the shape of the radiator patch by introducing the slots. A single layer wide-band rectangular patch antenna with achievable impedance bandwidth of greater than 20% has been demonstrated in ref. [6]. In this paper a wideband W slot stacked microstrip antenna with compact size is presented which gives a bandwidth of around 25.78% with high efficiency of 99% and a high gain of approximately 6dBi. The antenna is

suitable for WLAN and other wireless application ranging from 4.381GHz to 5.668GHz.

Figure 1. Geometry of proposed microstrip antenna

Figure2.Side view of proposed microstrip antenna.

2012 International Conference on Communication Systems and Network Technologies

978-0-7695-4692-6/12 $26.00 © 2012 IEEE

DOI 10.1109/CSNT.2012.16

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2012 International Conference on Communication Systems and Network Technologies

978-0-7695-4692-6/12 $26.00 © 2012 IEEE

DOI 10.1109/CSNT.2012.16

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2012 International Conference on Communication Systems and Network Technologies

978-0-7695-4692-6/12 $26.00 © 2012 IEEE

DOI 10.1109/CSNT.2012.16

32

2012 International Conference on Communication Systems and Network Technologies

978-0-7695-4692-6/12 $26.00 © 2012 IEEE

DOI 10.1109/CSNT.2012.16

32

2012 International Conference on Communication Systems and Network Technologies

978-0-7695-4692-6/12 $26.00 © 2012 IEEE

DOI 10.1109/CSNT.2012.16

32

2012 International Conference on Communication Systems and Network Technologies

978-0-7695-4692-6/12 $26.00 © 2012 IEEE

DOI 10.1109/CSNT.2012.16

32

2012 International Conference on Communication Systems and Network Technologies

978-0-7695-4692-6/12 $26.00 © 2012 IEEE

DOI 10.1109/CSNT.2012.16

31

2012 International Conference on Communication Systems and Network Technologies

978-0-7695-4692-6/12 $26.00 © 2012 IEEE

DOI 10.1109/CSNT.2012.16

31

2012 International Conference on Communication Systems and Network Technologies

978-0-7695-4692-6/12 $26.00 © 2012 IEEE

DOI 10.1109/CSNT.2012.16

31

II – DESIGN OF RECTANGULAR PATCH The length and the width of the patch antenna are

calculated by the equations (1) – (4) given in [16, 17].

Where c is the velocity of light, rε is the dielectric

constant of substrate, f is the operating frequency, L and

W are the patch length and width, and effε the effective

dielectric constant.

2/)1(2 +=

rfcW

ε (1)

( ) ( ) 21

1012

12

1 −

���

��� +−++=

Whrr

effεεε (2)

( )

( ) �

�� +−

�

�� ++

=Δ

813.0258.0

262.0300.0412.0

hWh

W

hl

eff

eff

ε

ε (3)

lf

cLeff

Δ−= 22 ε

(4)

III –ANTENNA GEOMETRY AND DESIGN Figure 1 depicts the antenna geometry. The Antenna is designed using air as a dielectric of height 10 mm between the ground plane and patch. The Length and width of the ground plane is 17.2mm by 20 mm. (L × W) From the ground plane at a height of 10 mm a parasitic patch of W slot is digged of dimensions 7.2mm by 10 mm(L1 × W1). The slot cutting and stacking is done to improve the bandwidth of the microstrip antenna which in this case is achieved to 25.78%. Figure 3 shows the 3dimensional structure of proposed antenna as obtained from IE3D simulation software. The green color shows the ground plane and yellow color is the slotted parasitic patch and the red color shows the location of the probe.

Figure 3. 3D structure of the proposed microstrip antenna

IV – RESULTS AND DISCUSSIONS

Figure 4 shows the return loss graph of microstrip antenna which is about -16db. The simulated and measured result is shown which is almost same and hence justifying the result. The W slotted stacked configuration antenna gives a bandwidth of 25.78% covering the range of 5.15GHz. to 5.35GHz and 5.725GHz. to 5.825GHz. making it suitable for WLAN and other broadband applications.

Figure 4. Return loss Vs frequency plot of proposed microstrip antenna

333333333333323232

Figure 5 & Figure 6 shows the Elevation pattern and the 3D radiation pattern. The radiation pattern at 4.87GHz frequency is shown in the figure which is omni directional. The component E theta, phi = 0(deg) is shown giving a power gain of 2.58954dB and E phi, phi = 0(deg) is giving a power gain of 3.44845 dB which is appreciably good. Also it is clearly shown in the figure that there are very less side and back lobes radiations in the proposed antenna and hence reducing the losses.

Figure 5. Radiation pattern of the proposed microstrip antenna. .

Figure 6. 3D radiation pattern of the proposed microstrip antenna Figure 7 shows the Gain Vs Frequency curve. The gain achieved of the proposed antenna is around 6dBi with a bandwidth of 25.78 % and efficiency as high as 99%.

Figure 7. Gain Vs Frequency plot

Figure 8 shows the Efficiency Vs Frequency plot which shows that antenna efficiency is quite high and is about 99 %. The structure is simulated using IE3D simulation software.

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Figure 8. Efficiecy Vs frequency plot of proposed microstrip antenna.

V – CONCLUSION

A wideband W slot stacked microstrip antenna has been designed for WLAN and other broad band applications. The proposed geometry is designed using air as a dilectric between the two layers. The stacked configuration has given a appreciably good bandwidth and efiiciency of 25.78% and 99% respectively. The improvement in efficiency and gain alongwith appreciable bandwidth is the major achievemnet as in improving the bandwidth mostly the efficiency and gain is deterioted. It is concluded from the results that bandwidth of a microstrip antenna can be enhanced by simply cutting a slot of W shape of the given parameters.

VI – REFERENCES

[1] Ali, Zakir; Singh, Vinod Kumar; Singh, Ashutosh Kumar; Ayub, Shahanaz; “ E shaped Microstrip Antenna on Rogers substrate for WLAN applications” International Conference on Computational Intelligence and Communication Networks” IEEE 2011.

[2] Mohammad Tariqul Islam , Norbahiah Misran, Mohammed Nazmus Shakib , and Baharudin Yatim “Stacked Multiple Slot Microstrip Patch Antenna for Wireless Communication System” 5th International Conference on Electrical and Computer Engineering ICECE-IEEE 2008, 20-22 December 2008, Dhaka, Bangladesh. Proc. pp 784-786

[3] J.Y. Sze and K.L.Wong, “ Slotted rectangular microstrip an tenna for bandwidth enhancement ,” IEEE Transactions on Antennas and Propagation , vol . 48, pp . 1149 -1152, August 2000. [4] B.K. Ang & B.K. Chung “ A wideband E shaped Microstrip patch antenna for 5-6 GHz Wireless communications “ PIER,75, pp- 397-407. 2007.

[5] Ayoub, AFA, “ Analysis of Rectangular microstrip Antenna with air substrate” Journal of Electromagneti waves & applications” Vol 17 no-12 pp 1755-1766, 2003. [6] F. Yang, X. Zhang, Y. Rahmat-Samii, “Wide-band E-shaped patch antennas for wireless communications,” IEEE Transactions on Antennas and Propagation, vol. 49, pp. 1094-1100, 2001. [7] S. Egashira and E. Nishiyama, “ Stacked microstrip antenna with wide bandwidth and high gain ,” IEEE Tran sactions on Antennas and Propagation , vol . 44, pp . 1533–1534, November 1996. [8] Shivnarayan & Babu R Vishvakarma “Analysis of notch-loaded patch for dual-band operation”, Indian Journal of Radio & Space Physics. Vol.35, pp.435-442. [9] Mohammad A. A. Subhi H. Ahmad A. K. and Juma S. M. “Cavity model analysis of rectangular microstrip antenna operating in TM03 mode”, IEEE proc. pp. 0-2218-2223, 2006. [10] S. K Satpathy, Vijay Srinivasan, K P Ray and G Kumar, “Compact microstrip antennas for personal mobile communication”, IEEE proc. pp. 245-248, 1998. [11] Vinod K. Singh, Zakir Ali, “Dual Band U- shaped microstrip antenna for wireless Communication” International Journal of Engineering Science Technology, India, VOL 2 (6), pp 1623-1628, June,2010. [12] Pandey V. K. & Vishvakarma B R, “Theoretical analysis of linear array antenna of stacked patches”, indian j radio & space physics, 2005. [13]J. R. James and P. S. Hall, "Handbook of microstrip antennas," Peter Peregrinus Ltd, London, 1989.

[14] E. F. Bolinder, “Geometrical analysis of partially polarized electromagnetic waves,” IEEE Trans. Antennas Propag., Vol. AP-15, No. 1, pp. 37–40, January 1967. [15] G. A. Deschamps, “Microstrip microwave antennas,” Presented at the Third USAF Symposium on Antennas, 1953. [16] Balanis, C. A.,Antenna Theory, John Wiley & Sons,

Inc.,1997. [17] Pozar, D. M., \Microstrip antenna,"Proc. IEEE, Vol. 80, 79-81,1992.

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