Microwave transmission can be considered a line of sight (LOS) communication method, although it is not exclusively limited to that. Line-of-sight refers to the direct path between the transmitting and receiving antennas without any obstacles in between that could block or significantly attenuate the signal.
Microwaves, which are electromagnetic waves with wavelengths ranging from one meter to one millimeter, can be used for various types of communication, including satellite links, point-to-point wireless links, and cellular networks. In these applications, a clear line of sight between the transmitting and receiving antennas is desirable to ensure optimal signal strength and reliability.
However, it's important to note that microwaves can also propagate using other methods such as diffraction and reflection. Diffraction allows microwave signals to bend around obstacles to some extent, allowing communication to occur even if there isn't a direct line of sight. Reflection occurs when microwave signals bounce off surfaces such as buildings or the Earth's surface, which can also enable communication in non-line-of-sight scenarios.
So while microwave transmission typically relies on line-of-sight paths for optimal performance, it can also utilize other propagation methods to establish communication in non-line-of-sight situations to some degree.