On Coaxial Microcalorimeter Calibration

TL;DR

This paper details the calibration process of a coaxial microcalorimeter used as a primary power standard in the microwave domain, emphasizing the thermal load's role in measurement accuracy.

Contribution

It introduces a calibration method for coaxial microcalorimeters based on indirect heating thermocouples, enhancing measurement precision.

Findings

Calibration accuracy of about 10^-3 in the microwave range

Effective determination of microcalorimeter losses

Use of nearly ideal thermal load for improved measurement

Abstract

Primary power standards in the microwave domain are realized using a calorimetric technique, usually identified with the used measurement system, i.e., the microcalorimeter. It is adjusted for measurement of power ratios with a relative accuracy that, after an appropriate system calibration, is of order of 10^-3, at least in the microwave domain (1 GHz-18 GHz). Hereby we describe the calibration process implemented at the Istituto Nazionale di Ricerca Metrologica (Italy) for realizing a coaxial power standard based on indirect heating thermocouples. Particular regard is devoted to describe the nearly ideal thermal load used for determining the microcalorimeter losses and their influence on the measurand accuracy.