Coaxial Microcalorimeter system established as the primary standard of Microwave Power in the frequency range of 10 MHz to 18 GHz is an absolute method for the determination of effective efficiency of the ‘N’ type coaxial thermistor mounts. These thermistor mounts in turn are used for calibrating reference standard power mounts or power meter with sensors of different user organizations. In the microcalorimeter the total Microwave power dissipated in the thermistor mount and the dc-substituted power in the mount are measured simultaneously to determine the effective efficiency of the thermistor mount. Coaxial thermistor mounts, which are assigned calibration factors using coaxial microcalorimeter system, are used as reference standards to calibrate power sensors / thermistor mounts using direct comparison technique. VSWR is measured at all the desired frequencies with the help of Vector Network Analyzer based technique.
We have participated in APMP supplementary comparison of Microwave Power standard successfully. The results of NPLI were very close to the APMP reference value. We are also participating in International Comparison of Microwave power up to 18 GHz in June 2013 under Asia Pacific Metrology Programme (APMP) which is being piloted by NMI Japan in order to establish mutual degree of equivalence of our power standard with corresponding standards of advance level NMIs.
Automation Software for Coaxial microcalorimeter system has been developed indigenously based on a graphical programming environment. The program enables the computer to continuously acquire the raw data from the electronic equipments to evaluate the effective efficiency upto 18 GHz, display the graph in a real time environment and save the measured data in excel format.