1. What Is Antenna and Its Gain?
As we all know, the antenna is used to send and receive electromagnetic radiation, and it's also used to do the energy transformation. During the transmission, the oscillating current generated by the transmitter is sent to the antenna, and the antenna will transform it into an electromagnetic wave and then radiate it to its surrounding. While during the reception, the antenna needs to transform the wave into the oscillating current, then the circuit can decode and analyze.
If the antenna's gain is higher, the circuit loss will be less, and the energy's transfer efficiency will be better.
The gain value generally means the ratio of the power radiated in the direction of the maximum gain with the antenna and the energy power radiated by the ideal sphere at the same point. Therefore, we can calculate it using this expression:
And P1 has two reference benchmarks: one is the all-directional antenna with measurement unit “dBi”; the other one is the reference dipole antenna (the two-directional antenna) with measurement unit "dBd”.
0 dBd = 2.15 dBi
so when the proper antenna is connected, the device's input energy can be reduced to get the same radiation energy in the space.
But if the input energy of oscillating current is fixed, different antenna will cause different result. For example,
Here are two examples of different antennas：
The left antenna's gain is 2dBi , of which the waveform is shorter. The right antenna's gain is 5dBi or up, of which the waveform is much longer and much narrower. The radiation is horizontal, which makes the signal definitely stronger than the above model.
In conclusion, the length of antenna will have a relevant effect in its gain value. Theoretically, the longer the antenna is, the higher gain the antenna will acquire. Besides, the transfer efficiency is also important in the permeability of material and wastage of feeder cable to get higher transfer efficiency as well. To get a better permeability, the antenna manufacturers should choose better material like FRP and Ceram, shorten the extension cord as well as conduct better design in the circuit board to decrease the wastage
2. Ursalink Antenna
Ursalink offers different types of antennas including LoRa antennas, cellular antennas,Wi-Fi antennas and GPS antennas. The gain is ranging from 0.5dBi to 5dBi, but the exact gain range is different respectively.
For cellular network installation, we still need to make sure whether the places to install antennas have great signal.
As for the LoRa network installation, if the end node is far from the gateway, it's better to choose an antenna with higher gain; if it's not that far, the standard antenna will be enough.
As for Wi-Fi/GPS antennas, the installation is much easier, you can just use the standard Wi-Fi/GPS antennas.
Finally, if the router/gateway is placed where the place is surrounded bymetal, for example, metal cabinet and container or the basement, you will need to add an extension cord to the antenna since the electromagnetic radiation will be quite weaker there. However, the extension cord should not be too long, otherwise you may cause extra wastage of feeder cable of the oscillating current.
To get full information about Antenna, try to visit Ursalink Accessories page.