CALIBRATION METHODS FOR ECE SYSTEMS WITH MICROWAVE SOURCES A FEASIBILITY STUDY
The authors investigated the feasibility of two methods for calibration of ECE systems, both based on the use of a microwave source. In the first method (called the Antenna Pattern Integration (API) method), the microwave source is scanned in space, so as to simulate a large area blackbody source. In the second method (called the Untuned Cavity (UC) method), an untuned cavity, fed by the microwave source, is used to simulate a blackbody. For both methods, the hardware required to perform partly automated calibrations was developed. The microwave based methods were compared with a large area blackbody calibration on two different ECE systems, a Michelson interferometer and a grating polychromator. The authors conclude that the API method is successful. A deviation of typically 20% with respect to the blackbody calibration is ascribed to the microwave power standard. Deviations of up to 50% were found when comparing the UC method with the blackbody calibration on the grating polychromator. This exceeds the estimated error. In application to the Michelson interferometer better consistency with the blackbody calibration is found. In view of these discrepancies, further development work in the area of cavity design is recommended. Both microwave based methods can be automated to a large degree. As far as time consumption and user interaction are concerned, they are competitive with the large area blackbody calibration method.
Bibliographic Reference: WRITE TO THE PUBLICATIONS OFFICER, JET JOINT UNDERTAKING, ABINGDON, OXON OX14 3EA (UK), MENTIONING REPORT JET-R(87)03, 1987
Record Number: 1989126008900 / Last updated on: 1988-02-01
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