Remote temperature measuring system for hostile industrial environments using microwave radiometry

摘要

A system and method for remotely measuring the temperature of an object using microwave radiometry that may be used in hostile environments. A single pole-single throw reflective PIN diode switch is operable in a PASS mode and a BLOCK mode. In the PASS mode, the switch passes the power received from the object to a low-noise block converter (“LNB”) for amplification. In the BLOCK mode, the switch blocks the object power and reflects the load noise power of an ambient temperature load to the LNB. A detector diode detects the amplified power output during both the BLOCK and PASS mode and the AC signal from the detector is converted to an output signal proportional to the difference in the noise powers detected in the PASS and BLOCK modes. A servo loop uses the output signal to generate a feedback signal to a noise injection diode that causes the diode to inject sufficient power into the LNB to automatically maintain a balance between noise power measured in the PASS mode and the combined noise powers measured in the BLOCK mode. The output signal is then used to compute the temperature of the object.