A good example of a fractal antenna as a spacefilling curve is in the form of a shrunken fractal helix Here, each line of copper is just small fraction of a wavelength.
A fractal antenna's response differs markedly from traditional antenna designs, in that it is capable of operating with good-to-excellent performance at many different frequencies simultaneously. Normally standard antennas have to be "cut" for the frequency for which they are to be used—and thus the standard antennas only work well at that frequency. This makes the fractal antenna an excellent design for wideband and multiband applications.
Many fractal element antennas use the fractal structure as a virtual combination of capacitors and inductors. This makes the antenna so that it has many different resonances which can be chosen and adjusted by choosing the proper fractal design. Note that such resonances may not be related to a particular scale size of the fractal structure: the scaling of the structure does not lead to a one-to-one scaling of resonances. This complexity arises because the current on the structure has a complex arrangement caused by the inductance and self capacitance. In general, although their effective electrical length is longer, fractal element antennas are physically smaller. Fractal element antennas are shrunken compared to conventional designs, and do not need additional components. In general the fractal dimension of a fractal antenna is a poor predictor of its performance and application.
Not all fractal antennas work well for a given application, much as not all conventional antennas are suitable for a given need. Computer search methods in simulation are commonly used to identify which fractal antenna designs best meet the need.
Although the first validation of the technology was published as early as 1995 (see ref.1) recent independent studies continue to show the superiority of the fractal element technology in real-life applications, such as RFID.
In addition to their use as antennas, fractals have also found application in other antenna system components including loads, counterpoises, and ground planes. Confusion by those who claim 'grain of rice'-sized fractal antennas arises, because such fractal structures serve the purpose of loads and counterpoises, rather than bona fide antennas.
Fractal inductors and fractal tuned circuits were also discovered and invented simultaneously with fractal element antennas (see reference 1 and reference 2-- patent 7256751). In the near future, fractals will have applications as inductors and tuned circuits. Fractal filters (a type of tuned circuit) are just one example where the superiority of the approach has been proven (see reference 6).
As fractals can be used as counterpoises, loads, ground planes, and filters, all parts that can be integrated with antennas, they are considered parts of some antenna systems and thus are discussed in the context of fractal antennas.
Fractal Antenna Aims at 2.9 to 14.6 GHz; This Compact Fractal Antenna Design Employs an Appollian-Shaped Gasket with Coplanar-Waveguide Feed, Achieving a Wide Impedance Bandwidth in a Simple-to-Fabricate Structure Suitable for Use with Integrated Circuits
Aug 01, 2012; Byline: I. SRIKANTH Master of Technology, Student RAJ KUMAR Professor BROADBAND ANTENNAS are needed for emerging applications...