XI Международная студенческая научная конференция Студенческий научный форум - 2019

Mirror antennas are more often used than the others. They are used in various radio systems. This is due to the good characteristics in terms of the diversity of the obtained radiation patterns, low noise temperature, excellent properties in the band and relatively high efficiency.

The mirror antennas used in radiolocation provide the same signal over the coverage area, allow you to form different DMs with a common mirror, including differential and total, as well as some antennas, fast beam swinging in a wide angular sector, and it is possible to create huge antenna structures with an effective opening surface several thousand square meters.

A two-mirror Cassegrain-type antenna is a confocal paraboloid and a hyperboloid (two reflecting surfaces) with an irradiator, which is installed in the second focus of the hyperboloid. The field is in phase with the opening,

equal distances from the focus to the aperture along the broken line.

Despite the lack of shading by the antennas aperture of a small mirror and the reverse response of a small mirror to the feed, a two-mirror antenna has a number of

advantages over single-mirror: compactness, more uniform distribution of excitation over the aperture, higher noise immunity, surface utilization factor (0.6-0.65), the possibility of shortening the microwave path and placing the main part of the structure behind the mirror, which is important for monopulse radars.

The work of the antenna according to the Cassegrain principle consists in the reflection of emitted electromagnetic field by the irradiator from the hyperboloid (second mirror), which falls on the surface of the paraboloid (first mirror), and is radiated into space in a manner similar to radiation from a flat in-phase surface.

      Now the rapid development of complex radar systems, radiometry, radio navigation, communications and radio astronomy, providing radiation and receiving radio waves is an integral function of antenna devices.

In the applications of radio systems to the antennas must meet a list of technical requirements. The conditions and positioning of the antennas have a strong impact on the characteristics of radio systems.

All characteristics related to antennas and antenna systems are more dependent on the operating frequency band.

It is necessary to conduct a computer experiment using the AROUND program for estimating the parameters of a mirror antenna at the frequency of 18 GHz,

as well as to estimate the parameters of the antenna in the frequency band 16 ÷ 26 GHz.

Almost always, you can change the antenna parameters under the requirements of a specific task.

     In connection with the great demand of mirror antennas in various industries, the calculation of the mirror antenna is actual.

Results comparison of antenna parameters in the frequency band are presented in the table.

In the antenna of this type “ANDREW VHLP2-180-NC3 (A)”, a rectangular waveguide with the main type of wave is used as a connection of the power supply and a circular waveguide.

Literature:

Sitnyanskiy B.D. Description of the antenna calculation programs (ANT package) –M.: - Vladimir,2003.

Sitnyanskiy B.D., Sadovskiy N.V., Gavrilov V.M. Antennas and microwave devices. Guidelines for course work. - M.: -Vladimir,2004.