What devices use microwaves?

Microwaves have lots of uses, some commercial (such as microwave ovens, satellite TV, and weather radar) and some military (such as missile guidance systems), applications in the field of scientific research, microwaves monitor the environmental health of our planet as well as to learn more about the universe. Research scientists use microwaves in two types of systems: active and passive. In active systems, such as radars, scientists send out microwaves and examine what comes back. In passive systems scientists simply look for naturally occurring microwaves and use them to learn more about the objects that emit the waves.