What is dBi in antenna?

dBi is a unit of expression for antenna gain.

Specifically:
Under the condition of equal input power, the ratio of the power density of the signal generated by the actual antenna and the ideal radiating element at the same point in space. It quantitatively describes the degree to which an antenna concentrates and radiates input power. The gain is obviously closely related to the antenna pattern. The narrower the main lobe of the pattern and the smaller the side lobes, the higher the gain. Antenna gain is used to measure the ability of an antenna to send and receive signals in a specific direction, and it is one of the most important parameters for selecting a base station antenna.

Simply put: the larger the dbi, the higher the antenna gain. The better the effect; however, the improvement of the effect is also relative, to a certain extent, not only the improvement is limited, but also the price is not cheap, and it is very likely to cause other problems.

Generally, the antenna gain of the gsm directional base station is 18dBi, and the omnidirectional one is 11dBi....