A H.P. 8409-B Based Power Sensor Calibration System

Accurate manual calibration of RF/microwave power sensors (Thermistor, Thermoelectric and Diode Bridge mounts) is quite complex. The complete calibration process requires the measurement of both the complex impedance and Effective Efficiency of the device under test. The Calibration Factor and Statement of Uncertainties are calculated. The entire procedure can be streamlined by using computers to reduce data and to produce the Report of Calibration. Precision manual measurements at twenty-four frequency points (50 MHz to 18 GHz) usually take about six man-hours to complete. This paper describes an automated system that will produce comparable results in approximately twenty minutes. The system combines the Hewlett-Packard 8409-B Vector Automated Network Analyzer and the Hewlett-Packard 436A-E10 Power Sensor Calibration System. The resulting system is more than just a simple combination. The system is currently used to calibrate a wide variety of thermistor, thermoelectric and diode bridge mounts manufactured by Hewlett-Packard, Wavetek and Boonton Electric. The list can be easily expanded to include other such devices. The system operates from 50 MHz to 18 GHz with a crossover point at 2 GHz.