International Research Journal of Engineering and Technology (IRJET) Volume: 04 Issue: 03 | Mar -2017
www.irjet.net
e-ISSN: 2395 -0056 p-ISSN: 2395-0072
Octagonal Fractal Antenna for 5 GHz Band: Modelling and Evaluations Mayank Jain1, Prof. (Dr.) R. P. Agarwal2 1Research 2Acadmic
Scholar, Shobhit University, Meerut, U.P., India Advisor, Shobhit University, Meerut, U. P., India
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Abstract—A microstrip octagonal patch antenna with
assume a circular sub array of eight elements with element separation d = λ/2, as shown in figure 1 [6-8].
large bandwidth is proposed for broadband application. The antenna is designed with patch on upper surface and ground on lower surface. By using octagonal patch antenna, large efficiency performance can be achieved. The large bandwidth can be obtain with control on the antenna size. Designing and study of proposed antenna for 0.1 – 5GHz is discussed. For large operational frequency experimental results provides the value of VSWR less than 2. Based on the results, the proposed antenna can be used for broadband wireless communication. Keywords—Patch antenna, Octagonal fractal antenna, Broadband, VSWR, Bandwidth, Return loss, Radiation pattern.
1. INTRODUCTION Recently, mobile devices are developed rapidly for transferring data, voice, image and video due to user demands of high quality communication [1]. In order to meet the demands, wireless technology for communication must be upgraded. Large bandwidth operations are required for carrying high quality data. However, current available electromagnetic spectrum in microwave bands is limited and almost reserved for many applications. Study on electromagnetic spectrum usage in microwave bands was done where available spectrum is about 15-85% [2]. Therefore, effective electromagnetic spectrum usage are studied and developed.
Fig 1: Geometry of Octagonal circular sub array generator From the properties of octagonal we know that, the interior and the exterior angles are of 1350 & 450 respectively [9]. So we conclude that
The array factor in terms of mathematical equation can be written as
In this paper, we propose a broadband antenna using an octagonal patch with a microstrip structure. The proposed antenna consist of an octagonal patch. The operational bandwidth can be adjusted by considering the size of octagonal patch [4-5]. Large operational bandwidth of almost 90% can be obtained by using the proposed antenna. Analysis and measurement results of the proposed antenna for broadband operation of 0.1-5 GHz are discussed and reported in detail.
Here
2. DESIGN CONSIDERATIONS In an array δ represents the scale factor. The scale factor δ controls the size of array with all recursive application. P represents the number of concentric octagons [10].
The conventional octagonal arrays were obtained by arranging the elements in a surrounding way by concentric eight elements, in an equilateral triangle. The conventional octagonal arrays can also be observed as having single element at the centre of the circle. For the analysis of this array design with the help of recursive application, we
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The total number of elements with P octagons can be represented as
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