General features:The radio frequency signal power output by the radio transmitter is transmitted through the feeder (cable) to the antenna, which
radiates out in the form of electromagnetic waves. After the electromagnetic wave reaches the receiving site. The antenna then
receives only a small fraction of the power and sends it to the radio receiver through the feeder. It can be seen that the antenna
is an important radio equipment for transmitting and receiving electromagnetic waves. There is no radio communication without the
antenna. A wide variety of antennas for different frequencies, different purposes, different occasions, different requirements and
other different situations of use. For many kinds of antennas, it is necessary to carry out appropriate classification. According
to the purpose of classification, can be divided into communication antenna, TV line, radar antenna, etc. : according to the
working frequency band classification, can be divided into short-wave antenna, ultrashort wave antenna, microwave antenna, etc. :
according to the directional classification, can be divided into omnidirectional antenna, directional antenna, etc. : draw shape
classification, can be divided into linear antenna, planar antenna, etc., and so on.