1. A TECHNICAL BRIEFING FOR AMATEUR RADIO OPERATORS
“FRACTAL AND METAMATERIAL ANTENNAS”
PRESENTED TO:
ARASWF
NAPLES, FL 34119
MARCH 2016
PRESENTED BY:
DR. AL TORRES
KP4AQI

2. January 2016: “Antenna Gain: Truths and Myths”
For Next Year 2016
January 2016: “Antenna Gain: Truths and Myths”
February 2016: “Slot Antennas: Wire Reciprocity”
March 2016: “Fractal and Metamaterial Antennas”

3. PRESENTATION OUTLINE WHAT IS A FRACTAL ANTENNA
FRACTAL ANTENNA ATTRIBUTES
FRACTAL DIPOLE ANTENNA CONFIGURATION
QUAD FRACTAL ANTENNA FOR 20 METERS
ELECTROMAGNETIC BANDGAP STRUCTURES
METAMATERIAL ANTENNAS
METAMATERIAL SATELLITE ANTENNA
METAMATERIAL STEERING ANTENNA
SUMMARY

4. WHAT IS A FRACTAL ANTENNA?
A fractal antenna is an antenna that uses a fractal, self-similar design to maximize the length, or increase the perimeter (on inside sections or the outer structure), of material that can receive or transmit electromagnetic radiation within a given total surface area or volume
Fractal antennas are also referred to as multilevel and space filling curves, but the key aspect lies in their repetition of a motif over two or more scale sizes or "iterations". For this reason, fractal antennas are very compact, multiband or wideband, and have useful applications in cellular telephone and microwave communications
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.

5. WHAT IS A FRACTAL ANTENNA? Cont.
A fractal is a rough or fragmented geometric shape that can be subdivided in parts, each of which is (at least approximately) a reduced-size copy of the whole. Fractals are generally self -similar and independent of scale
Fractals also describe many real-world objects, such as clouds, mountains, turbulence, and coastlines that do not correspond to simple geometric shapes
Fractals are space-filling contours; means having electrically large features can be efficiently packed into small areas. Since electrical lengths play an important role in antenna designs, this efficient packing can be used as a viable miniaturization technique

6. FRACTAL ANTENNA ATTRIBUTES
Large bandwidths…..almost as good as Log periodic antennas
Classical antenna configurations can be made in Fractal designs
Design theory is still heavy in mathematics
Both wire and slot designs available in Fractal Configurations
Gain issues are still being debated by the Electromagnetic community
Good efficiency when low loss materials are used
Smaller footprint configurations……smaller size with good performance

7. FRACTAL DIPOLE ANTENNA
Crossed dipoles suspended at /2 over ground plane
Crossed Stochastic Dipole
Footprint = 6.8 in2
Crossed linear Dipole
Footprint = 19.1 in2
Area Reduction 65%

8. QUAD FRACTAL ANTENNA FOR 20 METERS

9. Resonating structure has open-circuit boundary conditions
ELECTROMAGNETIC BANDGAP (EBG) STRUCTURES Genetically designed via-less structures
The EBG is a resonant surface
Behavior approximates that of the perfect magnetic conductor (PMC).
Provides in-phase boundary conditions at surface.
Allows an antenna to be placed very close (<< 1/10th ) to surface without the “short-circuiting” effect of ordinary metal.
Closely spaced antenna will be much more tolerant to height variations than that of dipole spaced /4 over PEC plane.
In-Phase Reflection
Incident Wave
Resonating structure has open-circuit boundary conditions
Antenna
Antenna

10. but the resonating structure can be tunable/steerable
WHAT IS AN EBG?
An artificial “material” that exhibits the properties of a magnetic conductor The magnetic conductor has in-phase electrical boundary condition; the electromagnetic dual of an electrical conductor
EBG Range
PEC operation
PEC operation
An EBG is a resonating structure .... and hence has a finite bandwidth,
but the resonating structure can be tunable/steerable

11. METAMATERIALS ANTENNAS
Metamaterials offer potential for exciting new technologies, as well as for existing antennas to be made smaller, faster, and more efficient
Metamaterial is actually derived from the Greek work “meta” which means “beyond”
Metamaterials are defined as artificially engineered materials with properties that are not seen in natural materials
Materials consist of microstructures that are smaller than the wavelength of incident radiation
The electromagnetic properties of a material are defined by two material parameters: electric permittivity (  ) and magnetic permeability (  )
The index of refraction is a number that explains how the electromagnetic radiation propagates through a medium

12. METAMATERIALS ANTENNAS
The index of refraction (  ) is mathematically defined as the speed of light in a vacuum divided by the speed of light in the medium
= c/vp
C = velocity of light in a vacuum
vp = velocity of light in a medium
The index of refraction is related to the electric permittivity and the magnetic permeability by the Maxwell relation as follows:
 = 
Fooling Effect: slowing the electromagnetic wave in a medium sufficiently, the Emag will think it has traveled a longer distance thus we can reduce the size of antennas without compromises

13. METAMATERIAL SATELLITE ANTENNA
Metamaterial Mtenna designed for satellite communications
which is extremely thin Ku and Ka band. Electronically acquires,
steer, and lock a beam to any satellite without moving parts

14. METAMATERIAL STEERING ANTENNA
Metamaterial Rotating Antenna Without Moving
Moving Parts. Electronically Rotates To Provide
Maximum Signal Strength For Incoming Signal

15. SUMMARY WE HAVE DEFINED FRACTAL ANTENNAS AND CONFIGURATIONS
FRACTAL ANTENNAS ARE SMALLER THAN NORMAL ANTENNAS
FRACTAL ANTENNAS ARE STILL BEING DEVELOP; GAIN IS NOT AS GOOD AS NORMAL ANTENNAS. BANDWIDTH IS MUCH LARGER THAN NORMAL ANTENNAS
WE HAVE DEFINED METAMATERIAL ANTENNAS; THEY CAN PRODUCE VERY LARGE SIZE REDUCTIONS ON MOST ANTENNAS
WILL PROVIDE LARGE BANDWIDTHS AND STEERING ATTRIBUTES WITHOUT MOVING PARTS. TECHNOLOGY EVOLVING

16. MORE INFORMATION or COPY OF PRESENTATION
SEND AN TO THE FOLLOWING URL:
CONTACT ME AT:
AL TORRES
KP4AQI
P. O. BOX 24283
DAYTON, OH