What is necessary to prevent rain and snow from accumulating on the 5G antenna cover?
The coming 5G era! Toward realization of high speed/low latency/high reliability
The coming 5G era will have an impact in unexpected places like this!
Radio waves used in wireless communication are more easily absorbed by water as their frequency band increases. Therefore, it is known that if there is rainfall or snow accumulation on the antenna, the moisture causes radio wave attenuation, which can narrow the communication range or cause communication to be interrupted.
This radio wave attenuation becomes particularly noticeable at frequencies above several GHz, and is especially likely to occur in the several GHz to tens of GHz band used for 5G communication.
In other words, radio wave attenuation is more likely to occur in the high-frequency band during torrential rain or heavy snowfall.
Radio wave attenuation experiment
A water film was deposited on a polycarbonate plate, which is often used as a material for antenna covers, and radio wave attenuation was measured.
■ Adhesion of water droplets or water film to polycarbonate
Water film is generated
There is almost no water film
In our experiments, the surface treated with super hydrophobic coating HIREC (see right) repelled water and did not get wet, meaning that a water film was barely formed.
Radio wave attenuation amount depending on the condition of the polycarbonate sheet.
Radio wave attenuation occurs in both the sub-6GHz band and the millimeter wave band.
Please see the graph above. In the sub-6GHz band, the attenuation is approximately 20dB (blue triangle).
A 20dB attenuation translates to a radio wave transmittance of less than 10%.
In the millimeter-wave band, an attenuation of about 40 dB (blue star) is occurring.
In contrast, by applying our super hydrophobic coating (HIREC100), no water droplets or water films are formed, and we confirmed that radio wave attenuation can be reduced to almost zero (red line). It can also be seen that radio wave attenuation caused by HIREC100 itself is almost zero.
Please consider this as a measure to prevent signal attenuation and ensure stable 5G communication.
* A 50dB attenuation translates to a radio wave transmittance of less than 1%.
* The HIREC100 is a predecessor to the HIREC-R. The performance of both products is equivalent.