Electromagnetic waves above 100 MHz always travel in a straight line and signal always goes to  one particular station. Because it travels in straight line both sender and receiver needs to be in line of sight.

Microwaves can have wavelength ranging from 1 mm – 1 meter and frequency ranging from 300 MHz to 300 GHz.

Microwave antennas concentrate the waves making a beam of it. As shown in picture above, multiple antennas can be aligned to reach farther. Microwaves have higher frequencies but cannot penetrate wall and other obstacles that comes between.

Microwave transmission depends highly upon the weather conditions and the frequency it is using.

Microwaves are widely used for point to point  communications because their small signal strength  allows conveniently-sized antennas to direct them in narrow beams, which can be pointed directly at the receiving antenna