What is an antenna?

Antenna is a device that can workas a radiator and receiver of radio waves, it can be transmitting, receiving and transmitting-receiving. What is an antenna in the physical plane? These are specifically designed conductive elements connected to a radio receiver or radio transmitter.

Below are the principles of antenna operation and the main characteristics of its operation.

The principle of the antenna

Consider two modes, namely: transmit and receive mode.

Transfer Mode

In the transmission mode, conductive elements,the antenna components to which the current is fed through the 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 that propagates from the antenna in space.

Reception mode

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

Characteristics of antennas

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

Also, when studying antennas and their work, they usethe following auxiliary characteristics: the width of the radiation pattern by level, the level of the side lobes, the directivity factor, the scattering coefficient, the effective scattering area, and so on.

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