The antenna is one of the most important accessories for the RF transmitter and wireless modules, its good gain effect can greatly improve the transmission range and signal strength from the wireless module. Therefore, it is very important to choose a suitable antenna for the wireless modules. But there are varies of antennas on the market. How do we choose an antenna for the wireless module?
1.Frequency band:
Every wireless module has working frequency band, such as 433MHz, 868MHz, etc.; The antenna has the same working frequency band too, the frequency band of the antenna must be the same as the frequency band of the wireless module when we select an antenna. Otherwise, the gain effect of antenna will be very poor. The difference of frequency band cause smaller radiation range of the antenna and accordingly it get a short transmission distance.
2.Gain value:
The gain value is a very important parameter of the antenna. The unit is dBi and the gain value is positive. The higher the gain value, the higher the gain effect on the wireless module.Therefore, a higher gain value antenna would be selected without considering other parameters when selecting the antenna.
3.VSWR(Voltage Standing Wave Ratio):
VSWR is the ratio of the amplitude of the standing wave and the voltage of the valley, which is also called the standing wave coefficient and the standing wave ratio. It is mainly used to describe the matching of the antenna. When the VSWR is equal to 1, it means that the impedance of the feeder and the antenna are completely matched, which is the most ideal case. When the VSWR is higher than 1, it means that some electric waves will be reflected back and become heat, hence the feeder is warmed up. And the reflected electric wave may generate a high voltage at the output of the wireless module and the module will be damaged sometimes. However, most of the antennas on the market have higher VSWR value than 1 and less than 1.5. Some bad quality antennas have a higher VSWR value than 1.5 or even higher. The higher the VSWR, the more the transmitting waves ,the higher the heat and the greater the chance to damage the module. Therefore,when we select an antenna, we must pay attention to the VSWR of the antenna. It is better to check it by ourselves.
4. Working environment:
Each project has a different working environment, so the antennas used will be different. If the environment is in harsh and many sources of interference. Superbat recommend you to select a high gain external antenna, such as rod antenna, sucker antenna and Yagi antenna. The high-gain antenna can increase the anti-interference ability. If you need to consider installing the antenna together with the RF transceiver module inside the device, spring antenna or FPC is a better choice.
Note:
1. High-power wireless modules can not use small-gain antennas, such as spring antennas, FPC antennas and other built-in antennas with small gains. Because the module signal radiation will not be transmitted if the high-power wireless modules use small gain antennas, resulting in bad transmission effects and accordingly it cause problems such as short distance.
2.Low-power wireless modules can use high-gain antennas, the higher the gain of the antenna, the better the performance of the module.
3.The higher the position of the antenna, the better the signal transmission and the longer the transmission range will be. It should be kept open and far away from metals,buildings and other interference sources.
4. We Superbat is professional supplier and manufacturer of RF antennas and custom service for these products.the reliable technical support and good prices can be provided. welcome to contact us if you have any questions.