Patent ID: 8447385

Claim:
A microwave handheld radiometer for measuring subsurface tissue temperature of a subject, said radiometer comprising: a microwave antenna disposed relative to a handheld radiometer housing and adapted to electromagnetically couple to a skin surface of a subject; a circulator having a first circulator input and a second circulator input, said first circulator input electrically coupled to said antenna via a microwave feedline; a switch electrically disposed between said antenna and said microwave feedline, said switch having a calibrate state and a measure state; a noise source electrically coupled to said circulator, said noise source being configured to provide a first source of thermal noise at a first temperature and a second source of thermal noise at a second temperature and wherein said noise source is switched between said first source and second source upon external command; and a detector creating a detector output wherein said radiometer further including means for toggling said switch between said states, in which said switch is placed into said measure state automatically based on a threshold reading of a proximity sensor disposed on said housing, said proximity sensor providing a signal indicative of distance from said subject and including at least one sensor for measuring surface temperature of said subject.