FZP Antennas for satellite reception

SUMMARY FZP ANTENNAS FOB SATELLITE RECEPTION Aperture antennas are used in satellite communications at microwave frequencies. For this reason, today, paraboloidal antennas are often used. However, these antennas are difficult to manufacture and their performances may be degraded due to rain and snow. These disadvantages have led to use planar antennas. In this dissertation, planar FZP(Fresnel Zone Plate) antennas consisting of Fresnel zones arranged consecutively a dielectric substrate materials are examined. Performance characteristics at 10.95-11.7 GHz band were obtained. Several FZP antennas were realized and their performances were tested. Characteristics of FZP antennas are frequency dependent. Bandwidths of these antennas is 15-20 % of their design frequencies. 3-dB beamwidth is close to that of reflectors. Their sidelobes and cross-polarizations levels are greater than those of the reflectors. Their efficiency are less than those of reflectors. Efficiency of FZP antennas, depending on their types, varies between 8 and 70 percent. As their efficiency is increased, their manufacturing becomes difficult. Efficiency of a simple FZP antenna is approximately between 8 and 30 percent. Several hand-made FZP antennas have shown good results for pictures from broadcasting satellites. Consequently, FZP antennas, when high gain is not necessary, can be easily manufactured and used. Key words s FZP, diffraction, antennas, reflector antennas, satellite broadcasting reception. VII