Fractal Antenna Basics | Fractal Antenna design,working operation
This page covers Fractal Antenna basics. It mentions benefits or advantages of fractal antenna. It mentions Fractal Antenna working operation and design of a Fractal Antenna.
We know that traditionally, antennas are designed based on different applications and different frequencies of interest. Fractal antennas are designed to be used for multiple frequency bands and applications. They have unique characteristics based on geometry and design of fractals.
The fractal geometry based shapes have been found in the nature. They have various applications which include image compression, lightning etc.
Following table mentions types of fractal geometries and their unique characteristics/features. These geometries are used in the design of fractal antenna as explained below.
|Fractal Geometry type||Description|
|Sierpinski Gasket||It uses triangles during design. In this type, black areas represent metallic conductor and triangular areas represent region from where metals have been removed.|
|Sierpinski Carpet||It uses squares instead of triangles.|
|Koch Curves||It starts with straight line which is partitioned into 3 parts. Here segment at the middle is replaced with two others having same length. The first such iteration is known as generator. Similar to this, other geometric constructions have been produced using higher number of iterations.|
|Cantor Set||This type of geometry is produced using algorithms. The set becomes sparser when number of iterations increased.|
Benefits or Advantages of Fractal Antenna
Following are the advantages of fractal antenna.
By applying fractal concept to antenna elements following can be achieved.
• Smaller antenna size can be obtained along with excellent efficiency and gain.
• Resonance frequencies which support multiple bands can be achieved.
• The antenna can be easily optimized for target gain value.
• Wideband frequency response can be obtained.
• It is simple and robust whose characteristics depend on geometry and does not depend on discrete components.
Fractal Antenna Working operation | Fractal Antenna Design
Different feeding techniques are employed in the design of antenna as
summarized below. Each of these feeding techniques have their uniques advantages and
• Microstrip Line feeding
• Coaxial Probe feeding
• Aperture Coupled feeding
• Proximate Coupled feeding
• CPW feeding
We will take example of Sierpinski Carpet Antenna with CPW feeding technique in order to understand working operation of a fractal antenna. Let us understand design of fractal antenna with this example type. Fractal antenna using sierpinski carpet geometry is depicted in the figure-2.
Usually ground plane geometry is kept fixed and radiating patch structure on top is varied to obtain different radiation pattern as well as bandwidth. This type of antenna is suitable for WLAN application in order to support multiple frequency bands viz. 2.4 GHz, 5.2 GHz and 5.5 GHz. It can also be used for WiMAX devices operating in frequency bands viz. 2.5 GHz, 3.5 GHz and 5.5 GHz.
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