LoRa node and LoRaWAN gateway | Lora antenna
Antenna is a critical part of the RF chip. When LoRa devices (such as LoRa nodes and LoRaWAN gateways) transmit and receive data, the frequency band used is also in the radio frequency band. Therefore, the selection of antennas is also particularly important.
1, Basic knowledge of the antenna
The common antennas include PCB antennas, ceramic antennas, spring antennas, rod antennas, fiberglass antennas, and suction antennas.
The performance of the antenna mainly has the following parameters: impedance, standing wave ratio, and antenna gain.
The standard value of impedance is 50 ohms, and the standing wave ratio is 1. The logos match perfectly, and the greater the antenna gain, the better.
2, How to choose the antenna
When choosing, the shape of the antenna itself is not the most important.
What matters are the parameters, the environment of the site and the constraints of the structure.
For the LoRa node, because in actual projects, most projects require the structure of the LoRa node to be small, therefore, the LoRa node generally chooses a spring antenna.
As for the LoRaWAN gateway, in general, there is no requirement for the volume of the gateway in actual use, so the LoRaWAN gateway is generally not limited by the volume. Therefore, when selecting an antenna, it is recommended to use a fiberglass antenna. Because the fiberglass antenna has good electrical insulation, strong wave permeability, and better signal. Therefore, if the size is not considered, the fiberglass antenna is given priority.
In addition, for outdoor LoRaWAN gateways, the environment is relatively harsh, while FRP has strong weather resistance, corrosion resistance, UV resistance, aging resistance, and impact resistance. It can be suitable for various complex environments, so people are more inclined to choose fiberglass antennas for LoRaWAN gateways.
3, Precautions for using the antenna
The antenna should be placed as far away from the ground as possible and not close to large metal objects.
In addition, the actual frequency band used by the LoRa antenna should be consistent with the frequency range supported by the LoRa antenna.
For example, the 915M antenna should be used in the 915M frequency band. If the 915M antenna is used in the 868M frequency band, the effect will be poor.
Finally, you need to pay attention to the antenna feeder, ufl-to-sma adapter cable, the length of the suction antenna cable, etc., especially when the cable length is long, you need to fully consider the attenuation effect of the cable on the signal.
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