| In signal receiving, the satellite antenna works as a device to marshal and concentrate the Hertzian wave energy permeated in the air through its paraboloid reflectors. In signal transmitting, is works in an opposite way of receiving to project the Hertzian wave beam onto the satellite that it is communicating with. There is a device called feed positioned at the focus point of the paraboloid to collect in or transmit out the signals. Please refer to the conceptual diagram shown in
the following figure.
The simplest and earliest antenna is the so-called front feeding parabolic antenna. Later it developed into the Cassegrain and Gregorian dual reflector antennas. The ring focus antenna, which is the main product from our company, is the further development in the antenna design, which greatly improved the performance, especially for the medium or small sized antennas.
Because the wavelength in microwave band is very small, such as for the satellite communications, in C-band, 4–6 GHz, it is less than 50mm and in Ku-band, 12–14 GHz, it is only about 20mm, the characters of the Hertzian wave is quite similar to the optical wave. Based on this we adopt the theory of the geometrical optics in design the parabolic reflector for our antenna products.
The main reflector of the ring-focus antenna is a circumrotating paraboloid and the sub-reflector is a circumrotating ellipsoid. In signal transmitting, the Hertzian wave emitted from the feed and projected to the apex of the sub-reflector, is reflected to the edge of the main reflector, whereas the wave projected to the edge of the sub-reflector is reflected to the center of the main reflector. In terms of the geometrical optics, by going through this reflecting process, the Hertzian wave forms a strong beam parallel to the central axes of the antenna, just like a light beam from a flashlight, which points to the communicating satellite. Please refer to the Figure 2.
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