Antenna feed

A radio <a href="/facts/Transmitter/nFYghtKv">transmitter</a> or <a href="/facts/Radio_receiver/5olDTxkg">receiver</a> is connected to an <a href="/facts/Antenna_(radio)/pGlcXBvc">antenna</a> which emits or receives the <a href="/facts/Radio_wave/XmB6WPpF">radio waves</a>. The antenna feed system or antenna feed is the <a href="/facts/Electrical_cable/Dhzlz5hn">cable</a> or <a href="/facts/Electrical_conductor/BSuyupLP">conductor</a>, and other associated equipment, which connects the transmitter or receiver with the antenna and makes the two devices compatible. In a radio transmitter, the transmitter generates an <a href="/facts/Alternating_current/qxICS3xa">alternating current</a> of <a href="/facts/Radio_frequency/aWku7h4R">radio frequency</a>, and the feed system feeds the current to the antenna, which converts the power in the current to radio waves. In a radio receiver, the incoming radio waves excite tiny alternating currents in the antenna, and the feed system delivers this current to the receiver, which processes the signal.
To transfer <a href="/facts/Radio_frequency/aWku7h4R">radio frequency</a> current efficiently, the <a href="/facts/Feedline/y9qa2CWa">feedline</a> connecting the transmitter or receiver to the antenna must be a special type of cable called <a href="/facts/Transmission_line/cYlqaPo3">transmission line</a>. At <a href="/facts/Microwave/HmVSN31Y">microwave</a> frequencies, <a href="/facts/Waveguide_(radio_frequency)/M60l8qrm">waveguide</a> is often used, which is a hollow metal pipe carrying radio waves. In a <a href="/facts/Parabolic_antenna/8EpLcN6q">parabolic (dish) antenna</a> the feed is usually also defined to include the feed antenna (<a href="/facts/Feed_horn/8cKuAR2X">feed horn</a>) which emits or receives the radio waves. Particularly in transmitters, the feed system is a critical component which <a href="/facts/Impedance_matching/0mdy9TAp">impedance matches</a> the antenna, feedline, and transmitter. To accomplish this, the feed system may also include circuits called <a href="/facts/Antenna_tuning_unit/ExtH4QI2">antenna tuning units</a> or <a href="/facts/Matching_network/0mdy9TAp">matching networks</a> between the antenna and feedline and the feedline and transmitter. On an antenna the feed point is the point on the driven antenna element at which the feedline is connected.

Antenna feed open-in-new

Antenna feed