The principle of radiation of electromagnetic waves (1978)

It is shown how electromagnetic waves are emitted into space (a large transmitter emits vons).

Different types of antennas - tower antenna, mast antenna, in-phase horizontal antenna, pyramidal horn, surface wave antenna, paraboloid of rotation.

The replacement of the antenna by a system of elementary emitters is shown, the radiation fields of which are vector-summed in space at each moment of time.

Elementary emitters include an electric dipole (formulas are derived), a magnetic dipole (formulas are derived), a Huygens element (formulas are derived).

One of the models of an elementary electric dipole is presented (interactive graphs are shown).

The process of the appearance of an electromagnetic field is shown.

In the frame there is a coordinate system with three axes, formulas and expressions that define the complex structure of the field are derived.

The space around the dipole can be divided into three zones - the near or quasi-stationary zone, the intermediate or induction zone, the far or wave zone.

The time variation of the electromagnetic field in the near zone is shown (the magnetic field here is a vortex).

Electric has two components - vortex and potential.

Reactive electromagnetic field.

The radiation field.

Both the radiation field and the reactive field are present in the near zone.

Formulas and expressions for the components of the field are displayed on the screen.

Bio-Savard's law - the formula is derived.

The electric field of an electrostatic dipole (formulas, expressions are shown).

Intermediate zone - formulas, expressions describe the distribution of the field.

The far zone - formulas, expressions for describing the distribution of the field in space (in this zone, the field is transverse and acquires the properties of a plane wave - formulas are shown).

It is shown on what the extent of each zone depends (on the wavelength of electromagnetic radiation), formulas are derived.

The graph shows the distribution of the radiation field of the dipole in space depending on the angular coordinates - it is considered either by the field strength (the formula is derived) or by the power flux density (the formula is derived) and is determined by the directional diagram.

The emissivity of the dipole is characterized by the radiation power, which depends on the amplitude of the current, the electric length of the dipole and the properties of the medium (the formula is derived).

Emission of electromagnetic waves by an elementary magnetic dipole - the formula is derived.

The structure of the magnetic dipole field is described.

The directional diagrams of the emitters of magnetic and electric dipoles are shown.

The emission of electromagnetic waves by the Huygens element is shown.

A more complex structure of the radiation field of such an emitter is shown.

The radiation pattern of such an emitter is shown.

The picture shows how electromagnetic waves go into space from the ship.

The radio transmitter is spinning.