Patent ID: 7760089

Claim:
A microwave detector capable of detecting whether an intruder is moving toward or away from a protected area, comprising: a microwave transceiver for transmitting and receiving a microwave signal directed toward a protected area producing a Doppler signal when reflected from a moving target; a chain of amplifiers having two or more amplifiers coupled to said microwave transceiver for amplifying said received Doppler signal, each amplifier including a gain representing a distance from the microwave transceiver such that each successive amplifier in said chain of amplifiers includes a successively higher gain, and a signal output of each amplifier represents a different distance from the microwave transceiver; and a controller for sampling an output of each amplifier of said chain of amplifiers, said controller including a memory for storing said output of each amplifier, and said controller determining whether said intruder is moving toward or away from the protected area based upon sampling a change in said output of each amplifier.