The main advantage of the parabolic reflector antennas is high directivity and then gain.
These antennas are used widely in microwave bands for analog and digital transmission such as terrestrial radio telecommunication, satellite air station, tracking applications, Radar, military purposes, etc.
Both of the major kinds, that is, single and double reflector, divide to front-fed and off-set types considering of feeding method. The off-set antennas compensate effect of aperture blocking instead of decreasing X-Polar Discrimination.
The feed assembly of the reflector antennas is the most sensitive part that affects directly on aperture performance and impedance characteristics, so it should be designed and manufactured carefully.
There are various kinds of feeds used in microwave antennas. In blow 3GHz applications, coaxial feeds are widely used because of low aperture blocking and good stability and withstanding, also easy installing on reflector.
In this report, the structure of two kinds of coaxial feeds used in 2.5GHz and 800 MHz bands is presented in detail. Also, some of the measuring and test methods together with some experimental results are explained.