Microcalorimetric measurement of the effective efficiency of microwave power sensors comprising thermocouples

2004 Conference on Precision Electromagnetic Measurements

Vremera²

2004

A key point in the realization of power standards with the microcalorimeter technique is the determination of the microcalorimeter losses and of their influence upon the measurand, i.e. the effective efficiency of the sensor used as thermal load. At IEN Galileo Ferraris, a simple procedure has been experienced that makes the microcalorimeter constant determination easier. Experiments done with a coaxial microcalorimeter in 50 MHz -18 GHz range have shown a significant accuracy improvement for the Italian national power standard.

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Updated Calibration Method for Coaxial Microcalorimeters

2004 Conference on Precision Electromagnetic Measurements

Vremera²

2004

“…effective efficiency η e , rather than absolute power. They are based mainly on the bolometric detection but, more recently, thermoelectric detection has been proposed at least for the coaxial systems, [5,6]. Both detection types allow tracing the HF standard to dc standard, a SI quantity, through the dc/1kHz power substitution [1].…”

Section: Introductionmentioning

confidence: 99%

Improving the primary power standard below 10 MHz with thermoelectric sensors

2008 Conference on Precision Electromagnetic Measurements Digest

Oberto

Sellone

2008

High frequency power standard is quite everywhere implemented using the Microcolormeter technique. At INRiM a twin type coaxial Microcalorimeter is used to measure the effective efficiency of thermoelectric detectors from direct current up to 40 GHz. However, below 10 MHz there is a lack of sensitivity that reduces the power standard accuracy. To work around the problem, we propose to calibrate the power detectors trough RF voltage measurements in the lowest frequency band.

“…In the past, the international community conducted a comparison, based on PTB suggestions [10], by circulating power sensors based on indirectly heated thermocouples among NMIs, with the aim of testing the suitability of thermoelectric detection for the coaxial microcalorimeter, as an alternative to the resistive power sensors, i.e., bolometers, no longer readily available on the market at frequencies greater than 18 GHz [11]. The Istituto Nazionale di Ricerca Metrologica (INRIM), formerly IEN Galileo Ferraris, participated in the international comparison mentioned in [11], i.e., CIPM key comparison CCEM.RF-K10.CL-power in coaxial PC 3.5 mm line system, with a coaxial microcalorimeter optimized for thermoelectric power sensors.…”

Section: Introductionmentioning

confidence: 99%

Comparison Between Thermoelectric and Bolometric Microwave Power Standards

IEEE Trans. Instrum. Meas.

Oberto

Sellone

et al. 2013

This paper describes a comparison of microwave power standards based on thermoelectric sensors to an analogous standard based on bolometric sensors. Measurements have been carried out with the classical twin-type microcalorimeter, fitted with N-connector test ports suitable for the frequency band 0.05-18 GHz. An appropriate measurand definition is given as being suitable for both standard types. A system accuracy assessment is performed applying the Gaussian error propagation through the mathematical models that interpret the microcalorimeter response in each case. The results highlight advantages and weaknesses of each power standard type.