The Definition Of Spiral Antenna

- Dec 20 2017 - A spiral antenna is a kind of antenna that can transmit and receive polarization electromagnetic signals rotated in space. The antenna is usually used in the ground station of satellite communication. An unbalanced feeder, such as a coaxial cable, is used to connect the antenna, the center of the cable is connected to the spiral part of the antenna, and the outer skin of the cable is connected to the reflector.
In appearance, the spiral antenna seems to have a spiral on a plane's reflector. The length of the spiral part should be equal to or slightly greater than a wavelength. The reflector is round or square, and the internal maximum distance (diameter or edge) of the reflector is at least 3/4 wavelengths. The radius of the helix is between 1/8 and 1/4 wavelengths, while the tilt angle of the 1/4 to 1/2 wavelengths is also guaranteed. The minimum size of the antenna depends on the frequency of the low frequency signal used. If the spiral or reflector is too small, the efficiency of the antenna will be severely reduced. In the axis of the spiral antenna, the energy of the electromagnetic wave is the greatest. A spiral antenna is usually composed of a plurality of spiral parts and a reflector. The whole group of antennas can be tracked vertically or horizontally to track a satellite. If the satellite does not run on the orbit, the azimuth of the antenna can be adjusted by the computer to track the orbit of the satellite.