What does a 4G antenna consist of?

Introduction: An antenna is a converter that converts guided waves passing on a transmission line into electromagnetic waves passing in unbounded space (usually free space), or vice versa.

Components used to transmit or receive electromagnetic waves in radio equipment. Engineering systems such as radio communications, radio, television, radar, navigation, electronic countermeasures, remote sensing, and radio geography, all that use electromagnetic waves to transmit information must rely on antennas. In addition, in terms of transmitting energy using electromagnetic waves, antennas are also required for non-signal energy radiation. Ordinary antennas are reversible, that is, the same antenna can be used as both a transmitting antenna and a receiving antenna. The basic characteristic parameters of the same antenna as transmitting or receiving are the same, that is the mutual theorem of antennas.

In antenna measurement, the working status of the antenna under test can be transmitted or accepted. This can be selected flexibly based on factors such as measurement content, measurement equipment, site conditions, etc. It can be seen from the principle of antenna interaction that the results of measuring antenna parameters in the two working states should be the same. But in actual measurement, the interaction principle must be used under certain conditions.

Condition 1: The antenna must be linear and passive, such as a satellite TV receiving antenna. Its feed is integrated with the tuner (LNB) and cannot be used for transmission.

Condition 2: The impedance matching of the transceiver system must be outstanding. Although there are multiple reflections between the antenna under test and the source antenna, the impact is not serious due to the attenuation of free space transmission. Impedance matching between source antenna, feeder, signal source, antenna under test, feeder and receiver is an important condition to meet the trading principle.

Condition 3: When exchanging antennas, passive equipment in the transceiver branch, such as power amplifiers, low-noise amplifiers, mixers, etc.