Classification of Antennas

With the development of microelectronics technology and wireless communication, antennas have become the infrastructure of wireless communication, with many uses and wide applications. Therefore, antenna knowledge has become the basic knowledge point that electronic engineers need to focus on learning.

1. The role of the antenna

When the antenna is used for transmission, it converts the high-frequency current in the circuit or the guided wave on the transmission line into a certain polarized space electromagnetic wave, and transmits it to a specified direction; Polarized electromagnetic waves are effectively converted into high-frequency currents in circuits or guided waves on transmission lines.

In short, the functions of the antenna are mainly divided into energy conversion and directional radiation or reception.

One of the most important parameters in the antenna equivalent circuit - the radiation resistance Rr, it can be considered that all the electromagnetic wave energy radiated by the antenna is absorbed by Rr.

2. Classification of antennas

①Classified by the nature of the work

It can be divided into transmitting antenna, receiving antenna and common antenna for sending and receiving.

②Classified by purpose

There are communication antennas, broadcast antennas, TV antennas, radar antennas, navigation antennas, direction finding antennas, etc.

③Classified by antenna characteristics

In terms of directionality: there are strong directional antennas, weak directional antennas, directional antennas, omnidirectional antennas, needle beam antennas, sectoral beam antennas, etc.

From the polarization characteristics: wired polarized antenna, circular polarized antenna and elliptical polarized antenna. Linearly polarized antennas are further divided into vertically polarized and horizontally polarized antennas.

In terms of frequency band characteristics: there are narrow-band antennas, wide-band antennas and ultra-wide-band antennas.

④ Classified according to the current distribution on the antenna

There are traveling wave antennas and standing wave antennas.

⑤ Classified by bands used

There are long-wave, ultra-long-wave, medium-wave, short-wave, ultra-short-wave, microwave, and millimeter-wave antennas.

⑥ According to the carrier

There are vehicle-mounted antennas, airborne antennas, satellite-borne antennas, and missile-borne antennas.

⑦Classified by antenna shape

There are whip antennas, T-shaped antennas, V-shaped antennas, rhombic antennas, loop antennas, helical antennas, waveguide port antennas, waveguide slot antennas, horn antennas, reflector antennas, etc.

In addition, there are Yagi antennas, logarithmic periodic antennas, array antennas, array antennas and linear array antennas, planar array antennas, conformal array antennas attached to the surface of some carriers, etc.