Patent ID: 8049620

Claim:
A method for detecting at least one of a fire and an intruder using passive reception of microwave radiation, comprising: passively receiving a first microwave radiation signal at a first receiver, said first receiver including a first antenna, a first frequency of said first passively received microwave radiation signal being indicative of a temperature of a source of said first microwave radiation; passively receiving a second microwave radiation signal at a second receiver, said second receiver including a second antenna, a second frequency of said second passively received microwave radiation signal being indicative of a temperature of a source of said second microwave radiation, wherein said first and second frequencies are within a first range of frequencies protected from active transmission in a geographic area encompassing a location of said first and second receivers, a second range of frequencies being between 0.5 and 1000 GHz for capturing a hydrogen line and a hydroxyl radical line and including said first range of frequencies; storing black body radiation frequency characteristics for a human body and for a fire in memory of a central computer for said second 0.5 to 1000 GHz frequency range; and comparing said first frequency with said second frequency of said first frequency range and with said black body radiation frequency characteristics of said second frequency range to determine a presence of at least one of a fire and an intruder at said central computer.