Monopole antenna

A monopole antenna is an antenna that has only one ' arm ' has in contrast to the dipole antenna whose mirrored on the conducting earth image replaces the other arm. Monopole antennas are used as transmitting and receiving antennas for very long wave, long wave, medium wave, short wave up in the VHF range. Examples of monopole antennas in the VHF range are car antennas for FM reception, where instead of the earth, the metallic body serves as a mirror.

Typical designs is the Marconi antenna ( λ / 4), which is often carried out as a self- radiating transmission tower. Other types of monopole antennas are, inter alia, L antennas, T antennas and Alexanderson antennas.

Information for the antenna gain of a monopoly depends on whether the radiation power for the comparison isotropically on the half-space ( 2π ) is distributed as a transmission tower with infinitely extended mirror surface adequately, or in all directions ( 4π appropriately around for a rod antenna on a fuselage ). Thus one finds for winning the quarter-wave monopole over the half-wave dipole both 1 and 2 (corresponding to 0 and 3 dBd ).