Microwave radio links are commonly used for wireless communication between two points, such as connecting cell towers, transmitting data between buildings, or providing internet access to remote areas. The choice of polarization (vertical or horizontal) in microwave radio links is an important consideration to ensure optimal signal transmission and reception. The main reasons for this focus are:
Minimizing interference: Microwave signals can be affected by various factors, including reflections, refractions, and scattering as they travel through the atmosphere. When two microwave links are operating in close proximity, having different polarizations can help reduce interference between the signals. If both links use the same polarization, there is a higher chance of signal degradation due to cross-polarization interference.
Reducing signal fading: Microwave signals can experience fading, which is the fluctuation of signal strength caused by interference and multipath propagation. When the polarization of the transmitter and receiver antennas is aligned (either both horizontal or both vertical), it reduces the impact of fading, resulting in more stable and reliable communication.
Overcoming obstacles: In urban environments and areas with many obstructions, such as tall buildings or mountains, microwave signals may encounter significant obstacles that can cause signal attenuation or blockage. By selecting the appropriate polarization, engineers can mitigate the effects of obstructions and improve signal propagation.
Avoiding signal cancellation: When microwave signals travel through the atmosphere, they may be partially or completely canceled out if their polarizations are misaligned at the receiving antenna. This phenomenon is known as cross-polarization discrimination. By aligning the polarizations at both ends of the link, signal cancellation is minimized, leading to better signal quality.
The specific choice of polarization (horizontal or vertical) depends on the particular installation and the surrounding environment. In practice, engineers analyze the terrain, obstructions, and other factors to determine the best polarization for each microwave radio link to achieve optimal performance and minimize signal issues.