Semiconductor millimeter and centimeter wave radiometer for the study of the radiation of an underlying surface
Abstract
A theoretical and experimental investigation of a superheterodyne radiometer system with input frequency converter and intermediate frequency modulation is presented. Conditions are found, at which the temperature sensitivity of the device does not deteriorate. A sensitivity function to external parameters (temperature, heterodyne power) of a radiometer system with intermediate frequency modulation and a Schottky diode frequency converter is presented and calculated. Use of a frequency converter at the second harmonic of the heterodyne permitted simplication of the radiometer design and the use of a semiconductor heterodyne. A 3 cm range intermediate frequency amplifier permitted the use of centimeter wave radiometer signals. Fluctuation sensitivity of radiometers with a 1 sec time constant is 0.3 K at 3.4 mm and 0.06 K at 3 cm.
- Publication:
-
NASA STI/Recon Technical Report N
- Pub Date:
- October 1979
- Bibcode:
- 1979STIN...8010477B
- Keywords:
-
- Microwave Radiometers;
- Schottky Diodes;
- Semiconductor Devices;
- Frequency Modulation;
- Heterodyning;
- Millimeter Waves;
- Temperature Effects;
- Instrumentation and Photography