Development of a 3.5-mm coaxial microcalorimeter for RF and microwave power standards at KRISS

This paper introduces a newly constructed type-N coaxial microcalorimeter that will serve as a primary power standard in Korea Research Institute of Standards and Science. The detailed design scheme of the microcalorimeter is presented, and its characteristics are evaluated. The performance of an adiabatic line was simulated with a finite-element-method-based tool and predicted. The measured insertion loss of the assembled adiabatic line was less than 0.15 dB. Frequency and power sweep measurements were performed on a reference standard to find a substituted power level that minimized the dual-element error. We also propose evaluation standards that can be used for the measurement of radio frequency loss. The correction factor for the effective efficiency of the reference standard was experimentally evaluated. We also present an uncertainty evaluation process and the corrected effective efficiency of a type-N coaxial reference standard.