Correction factor evaluation technique for a rectangular waveguide microcalorimeter

Cui, Xiaohai; Li, Yong; Gao, Xiaoxun; Song, Zhenfei; Sun, Weijie

doi:10.1109/arftg-2.2013.6737349

Cited by 10 publications

(8 citation statements)

References 4 publications

(4 reference statements)

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“…(3) is the correction factor of the microcalorimeter, and can be measured and characterized through inserting a foil short between the test port and the DUT in the microcalorimeter. Moreover as reported in [4], the correction factor g is the main uncertainty contribution for the effective efficiency measurements using a microcalorimeter.…”

Section: B Measurement Methods At Nim/nistmentioning

confidence: 89%

“…As discussed in [3][4], g in eq. (3) is the correction factor of the microcalorimeter, and can be measured and characterized through inserting a foil short between the test port and the DUT in the microcalorimeter.…”

Section: B Measurement Methods At Nim/nistmentioning

confidence: 99%

“…For its measurements, NIM and NIST will use their own-designed and wellestablished WR-15 microcalorimeter [2][3][4]. However, the measurement system at NMC, A*STAR was previously developed for the diode sensor (e.g., V8486A power sensor) measurements [5], and therefore the system needs to be modified slightly for measuring the thermistor mounts.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation and validation of a national WR-15 (50 to 75 GHz) power measurement system

Cui

Meng

Shan

et al. 2014

84th ARFTG Microwave Measurement Conference

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In this paper, we present some preliminary results from evaluation and validation of a national WR-15 (50 to 75 GHz) power measurement system, which has been upgraded for thermistor sensor (thermistor mount) measurements recently. The system is a physical realization of direct comparison transfer technique for microwave power sensor calibration. It has been evaluated and validated referring to a WR-15 microcalorimeter measurement system. Good performance has been observed preliminary, and some necessary improvement works have been planned in near future.Index Terms -Direct comparison transfer, microcalorimeter, power measurement, thermistor mount.

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Section: B Measurement Methods At Nim/nistmentioning

confidence: 89%

Section: B Measurement Methods At Nim/nistmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Evaluation and validation of a national WR-15 (50 to 75 GHz) power measurement system

Cui

Meng

Shan

et al. 2014

84th ARFTG Microwave Measurement Conference

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“…Similarly, the largest contributions to the correction factor uncertainties in the Foil Short and Offset Short evaluations were their measured reflection coefficients, |Γ FS | and |Γ OS |. In [2,3], a technique similar to the Foil Short evaluation was performed, but the analysis used a model of losses in the short. Our approach here also uses models for a flat short and offset short.…”

Section: Introductionmentioning

confidence: 99%

“…Our approach here also uses models for a flat short and offset short. It differs from [2,3] in that an additional heating source is not used and there is no need to estimate one of the thermal coefficients. …”

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confidence: 99%

Improvement in the evaluation of a rectangular waveguide microcalorimeter correction factora

Fang

Crowley

2014

29th Conference on Precision Electromagnetic Measurements (CPEM 2014)

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The correction factor of the National Institute of Standards and Technology's WR-15 (50 to 75 GHz) microcalorimeters has been re-evaluated. Use of modeled values for the reflection coefficient of a flat short and offset short instead of measured values results in lower uncertainties in the evaluation of the calorimeter correction factor obtained with these artifacts. The uncertainties are now comparable to that of an evaluation technique in which two calorimeter cores are directly connected to each other. Improvements in a fourth technique were also achieved with an improved measurement of the transmission coefficient of a line section. The differences in the derived correction factors are a little larger than would be expected based on the uncorrelated uncertainties. The source of the discrepancy has not been determined.Index Terms -Bolometer, Calorimetry, Millimeter wave measurement, Power measurement I. BACKGROUNDThe primary power standards between 50 MHz and 75 GHz at the National Institute of Standards and Technology (NIST) are microcalorimeters that are used to evaluate the effective efficiency of bolometric power sensors. The microcalorimeter measures temperature changes in response to direct current (DC) and radio, microwave, or millimeter-wave power (generically referred to as RF). This response is expressed aswhere e is the microcalorimeter thermopile voltage, k is a constant that depends on the thermal properties of the calorimeter, P DC and P RF are the DC and RF power absorbed in the bolometer device under test (DUT), g is the calorimeter correction factor and g ≅ 1. g deviates from 1 due to the different response of the microcalorimeter to RF and DC inputs. The most important contribution comes from RF losses in the calorimeter transmission line leading to the DUT. Uncertainty in g is an important, if not dominant, component of the uncertainty in an effective efficiency measurement. Special measurement techniques are used to evaluate g by arranging the apparatus so that the calorimeter transmission line losses and/or losses in the input section of the DUT can be isolated from the main losses in the bolometer resistor. Previously, the correction factors of a pair of WR-15 (50 GHz to 75 GHz) microcalorimeters used as standards at a U. S. government work, not subject to U. S. copyright NIST were evaluated with four techniques that were labeled Through, Line, Foil Short and Offset Short [1]. The standard (k = 1) uncertainties achieved with the four techniques were a weak function of frequency with typical values of 0.001, 0.003, 0.004, and 0.006 respectively (see Fig. 6 in [1]). The techniques use artifacts similar to those in a vector network analyzer (VNA) calibration, but the measurement process itself is different. The largest contribution to the correction factor uncertainty in the Line technique was the measured value of the artifact's transmission coefficient |S 21 |. Similarly, the largest contributions to the correction factor uncertainties in the Foil Short and Offset Short evaluations were th...

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Effects of the effective efficiency of the thermistor mount with WR-22(33 to 50 GHz) microcalorimeter

Cui

Yuan

et al. 2015

2015 85th Microwave Measurement Conference (ARFTG)

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Correction factor evaluation technique for a rectangular waveguide microcalorimeter

Cited by 10 publications

References 4 publications

Evaluation and validation of a national WR-15 (50 to 75 GHz) power measurement system

Evaluation and validation of a national WR-15 (50 to 75 GHz) power measurement system

Improvement in the evaluation of a rectangular waveguide microcalorimeter correction factora

Effects of the effective efficiency of the thermistor mount with WR-22(33 to 50 GHz) microcalorimeter

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