Multi Element Microstrip Antenna Arrays Using Electromagnetic Band Gap Structures

Author Name(s): K. Prahlada Rao, Vani R.M, P.V. Huanagund 1
Author Email: pra_kaluri@rediffmail.com

Abstract

This paper discusses the improvement in the performance of two, four and eight element microstrip antenna array using Electromagnetic Band Gap structures. The antenna arrays are designed at 6 GHz. The dielectric substrate used is FR-4 glass epoxy with dielectric constant of 4.2 and loss tangent of 0.0245. The two element conventional antenna array is producing bandwidth of 2.35 % and gain of 5.06 dB. The modified two element antenna array is producing greater bandwidth of 61.12 % and higher gain 8.34 dB. The four element conventional antenna array is producing bandwidth of 4.89 % and gain of 6.81 dB. The modified four element antenna array is producing improved bandwidth of 73.39 % and gain of 11.09 dB. The eight element conventional antenna array is producing bandwidth of 4.98 % and gain of 7.44 dB. The modified eight element antenna array is producing enhanced bandwidth of 85.74 % and healthier gain of 13.77 dB. All the modified microstrip antenna arrays show appreciable decrease in mutual coupling compared to their respective conventional antenna arrays. The radiation characteristics of the modified antenna arrays depict good reduction in back lobe radiation. The antenna arrays are designed using IE3D simulation software and measured results are obtained using vector network analyzer.

Introduction

The field of microwave antenna engineering has found innumerable applications in diversified areas of research in our everyday life. High data transfer rates accompanied with quality transmission and reception of information is the foremost criteria to be satisfied in communication systems. The boom in antenna engineering has opened a window for the discovery of new antennas called as microstrip antennas. Surface waves emanating from the dielectric substrate of microstrip antennas and arrays, lead to serious repercussions on antenna radiation properties and their characteristics. These antennas are employed in resonators, waveguides, high end communication systems and radars. The structure of a microstrip antenna consists of a dielectric substrate present between the radiating patch and finite ground plane. Microstrip antennas have pioneered many engineers because of their advantages like light weight, ease of fabrication, conformal and planar type of structure etc. [1-7]. In recent years, Electromagnetic Band Gap (EBG) structures have earned their place in antenna and microwave engineering because of their important feature of reduction of effect of surface waves on microstrip antennas and arrays. The EBG structures are periodic in nature and are used to reduce the mutual coupling between the antenna array elements. These structures also help microstrip antennas and arrays in attaining high bandwidths as these are classified as narrow band width antennas. Researchers have come up with various types of EBG design structures to enhance the performance of these antennas. [8-17].

Conclusion

The paper demonstrates the enhanced performance of two, four and eight element microstrip antenna arrays using EBG structures. The proposed microstrip antenna arrays show appreciable performance in terms of bandwidth (%) and reduction of mutual coupling. In the presence of EBG structures higher gains are also obtained. With the help of EBG structures the proposed microstrip antenna arrays are possessing good radiation characteristics in forward and backward directions. Moreover, the proposed eight element microstrip antenna array is showing the best performance compared to two and four element proposed microstrip antenna arrays which demonstrates the fundamental aspect of antenna arrays

 

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