radar
A method of detecting distant objects and determining their position, velocity, or other characteristics by analysis of sent radio waves (usually microwaves) reflected from their surfaces.
thermal agitation
The thermal motion of atoms and molecules in any object at a temperature above absolute zero, causing them to emit and absorb radiation.
terahertz radiation
Electromagnetic waves with frequencies around one terahertz.
Source: Boundless. “Microwaves.” Boundless Physics. Boundless, 21 Jul. 2015. Retrieved 16 Nov. 2015 from https://www.boundless.com/physics/textbooks/boundless-physics-textbook/electromagnetic-waves-23/the-electromagnetic-spectrum-165/microwaves-593-11170/