  In this diploma thesis we study the characteristics of electromagnetic fields
carrying orbital angular momentum (OAM) by analyzing and utilizing results
achieved in optics and then apply them to the radio domain to enable innovative
radio studies of space and the development of new concepts in wireless
communications.
  With the recent advent of fast digital converters it has become possible,
over a wide radio frequency range, to manipulate not only the modulation
properties of any given signal carried by a radio beam, but also the physical
field vectors which make up the radio beam itself. Drawing inferences from
results obtained in optics and quantum communication research during the past
10-15 years, we extract the core information about fields carrying orbital
angular momentum. We show that with this information it is possible to design
an array of antennas which, together with digital receivers/transmitters, can
readily produce, under full software control, a radio beam that carries
electromagnetic orbital angular momentum, a classical electrodynamics quantity
known for a century but so far preciously little utilized in radio, if at all.
This electromagnetic field is then optimized with the help of various antenna
array techniques to improve the radio vector field qualities. By explicit
numerical solution of the Maxwell equations from first principles, using a de
facto industrial standard antenna software package, we show that the field
indeed carries orbital angular momentum, and give a hint on how to detect and
measure orbital angular momentum in radio beams. Finally, we discuss and give
an explanation of what this can be used for and what the future might bring in
this area.
