The first use of radar is on the aircraft but currently the radar use on many applications. On the modern car also use radar that can detect the other car to avoid the collision between them.
On their development the great operation advantage of microwave radars during world war II was that they were relatively free from electronic counter measures (ECM) by the enemy. The necessary high power microwave pulses were generated by the cavity magnetism. Electronic warfare was now become a major threat to military radar systems, and modern radars have to be designed to reduce the effect of ECM. For example an antenna have been developed with increased resolving power but with very low side lobes so that active jamming connot penetrate into the receiver as readily as with earlier systems.