11-10-2016, 03:38 PM
1458663502-arpntobemodified.docx (Size: 1.03 MB / Downloads: 6)
Abstract:
In many commercial and defence communication systems,there is a need of compact antennas with high performance,considerable gain and compactness in size. The modern communication systems need such antennas which operates at multiband with wide bandwidth. One of the technique to satisfy that needs is the implementation of fractal geometry on the microstrip antenna radiator. It has been proved that fractal antennas have their own unique characteristics without changing the antenna properties. In the current paper, the performance of the microstrip patch antenna with Sierpinski gasket fractals as inverted triangles has been presented. The base antenna without fractals has been designed at 8.45GHZ operating frequency. As the base antenna offers narrow band width with single resonant frequency, triangular fractal geometry was implemented on the patch upto the second iteration to improve the gain and wide band width at multi bands. The fractal antenna characteristics are analysed at each iteration by using electromagnetic simulator HFSS 13
Introduction:
In modern wireless communication systems, the multi band and low profile antennas withwide bandwidth are in great demand for both commercial and military applications.To meet this needs one of the technique implemented is fractal shaped antenna elements. It has been proved that Fractal shaped antenna has some unique property as it represents self-similarity and repeats itself in several dimensions filling the space effectively.Due to this space filling technique in fractal geometry,the electrical size of antenna is increased with physical compactness. Due to the increase in the electrical size of the antenna performance is improved. Several geometries are available like Helix, Koch curve and Sierpinski carpet etc.In the current paper, Sierpinski fractal antenna with inverted triangle structure was implemented up to second order iteration. Its performance is observed to be varied from iteration to iteration of the triangular fractals.
Antenna Geometry:
The basic microstrip patch antenna is very compact in nature and its dimensions are taken as 30x34.64x2mm on substrate with line feeding. The proposed antenna consists of a Sierpinski gasket radiator with inverted triangle fractals on the top of the substrate material. A substrate material used isTeflon with dielectric constant of 2.1.In Sierpinski gasket geometry, the metallic patch is sub divided into inverted triangles in three iterations as shown in the fig.1.In the Iteration 1, a single Triangle is obtained by decomposing the rectangular microstrip patch. In the Iteration 2, the larger triangle is divided into 3 inverted equilateral triangles. In Iteration 3,the left over radiator is again filled by 3 inverted triangles of small size.The antenna is sourced by microstrip line feed with 50Ω impedance.
Conclusion:
The iteration1 antenna design resonates at three frequencies which are in X and Ku band with high return loss and gains. After iteration 2 the antenna resonates at two frequencies in Ku band but it offers high gain at 12.4 GHz with maximum power transfer. Iteration 3 antenna model resonates at two frequencies in X band with high return loss. As the antenna resonant frequencies after each iteration are in the range of either X or Ku band, these models are most suitable for Radar and Satellite applications with high compactness and with good performance and wide bandwidth of around 1000 MHz.