What is an antenna?

Andrey Kim
Andrey Kim
February 27, 2015
What is an antenna?

An antenna is a device that can work as a radiator and receiver of radio waves, it can be transmitting, receiving and transmitting. What is the antenna in physical terms? These are specifically designed conductive elements connected to a radio receiver or radio transmitter.

Below are the principle of operation of the antenna and the main characteristics of its work.

The principle of operation of the antenna

Consider two modes, namely: the mode of transmission and reception.

Transfer mode

In the transmission mode, the conductive elements that make up the antenna, to which current is supplied through a radio transmitter, generate an alternating magnetic field in space. An alternating magnetic field creates an alternating electric field, which again creates an alternating magnetic field. Thus, an electromagnetic wave arises, which propagates from the antenna in space.

Reception mode

In this mode, an electromagnetic wave falls on the conductive elements of the antenna, which, due to its alternating electromagnetic field, creates currents on them that are transmitted further to the radio receiver.

Antenna Characteristics

The main characteristic of the antenna - the radiation pattern - a graphical representation of the dependence of the antenna gain on the direction of the antenna.

Also, when studying antennas and their work, the following auxiliary characteristics are used: the width of the radiation pattern by level, the level of side lobes, the directivity, the scattering coefficient, the effective scattering area, etc.

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