Abstract

To fill the gap of intermediate frequencies 100 kHz–100 MHz for which still remains a lack of traceability of impedance measurements for recent measurement instruments, LNE has established the traceability of a 4 ports vector network analyzer (VNA) and applied the method of Suzuki to measure four terminal pair impedances (Z4TP). In order to establish the traceability of the 4 ports VNA, used to measure Z4TP, LNE has investigated successively two different ways. We have developed 4TP calculable thin-film resistors, and then we have established the traceability of the “Unknown Thru” calibration method. We will show the two approaches and the measurement results up to 10 MHz obtained for a 1 000 pF capacitor with the associated uncertainties.

Key words

Impédance
Vector Network Analyzer
Calculable Resistance
TRACEABILITY
standard

Abstract

This paper describes the development of a new power standard based on a commercial thermocouple sensor. A calibration with a twin microcalorimeter has been performed in order to determine the effective efficiency of the sensor. A calibration using thermal transfer allows us to validate the results got with the microcalorimeter. LNE has got a new power standard for low frequencies.

Key words

effective efficiency
uncertainty
thermocouple sensor
rf power standard
voltage standard
microcalorimeter
thermal transfer

Abstract

Two compensated current comparators with magnetic flux cancelling have been made in the 1970s by the LCIE (Laboratoire Central des Industries Electriques) as a reference for high current transformers calibration for currents up to 50 kA at industrial frequencies 50 Hz, 60 Hz and 400 Hz. They are associated with manually operated electronic equipments: an adjustable phantom burden and a ratio error set capable to provide with high accuracy the quadrature and the in-phase components of the current transformer errors. This article presents the work that has been done to entirely redefine theses devices by abandoning the idea of a direct servo system of the old equipment and replacing it by a software servo that offers high calibration stability, better incertainties and fully controllable by a remote computer via an USB connection, allowing full automation of the procedure.

Key words

compensated current comparator
phantom burden
ratio error set
current transformer
ratio error
phase-shift

Abstract

This paper presents our work for the measurement of the complex permittivity of liquids, carried out in the framework of a European Metrology research project entitled “Traceable measurement of field strength and SAR for the Physical Agents Directive”. One of he aims of this project was to establish the traceability of the specific absorption rate measurements to the SI up to 10 GHz. We use a vector network analyser to measure the S21 parameter of coaxial cells containing the liquid under test (a reference liquid or an equivalent tissue liquid). The method does not require the network analyser to be calibrated in terms of impedance. In fact, only the length of the coaxial cell and the working frequency need to be known.

Key words

ELECTRICAL METROLOGY
TRACEABILITY
COMPLEX PERMITTIVITY
REFERENCE LIQUID
SAR

Abstract

This paper presents the development of a new 2.4 mm coaxial twin load microcalorimeter and the development of the thermoelectric power sensors used as radiofrequency power standards. The effective efficiency is measured and results are presented for two types of sensors.

Key words

MICROCALORIMTER
COAXIAL LINE
HF POWER STANDARD
POWER SENSOR
THERMOELECTRIC SENSOR

Abstract

A method for determining the electromagnetic properties of Lead Zirconate Titanate (PZT) thin films is presented in this paper. At first we introduce a broadband characterization method based on the extraction of the intrinsic properties of substrate supporting a coplanar waveguide and then we perform an accurate on-wafer TRL calibration technique to measure the permittivity of the PZT thin film embedded in a coplanar waveguide.

Key words

S parameters
coplanar waveguide
PZT
permittivity
loss tangent
ferroelectric

Abstract

This paper describes the development of a power standard based on thermocouple sensors. This work has been done in the framework of the fabrication of a microcalorimeter to destination of a foreign National Metrology Institute. The calibration has been performed in order to determine both the effective efficiency and the uncertainty for 21 frequency points up to 50 GHz. LNE expands its capability for manufacturing broadband (DC-50 GHz) primary calibration systems for RF power.

Key words

effective efficiency
uncertainty
thermocouple sensor
rf power standard
voltage standard
microcalorimeter

Abstract

A system to mesure 8/20 μs (front time/time to half value) impulse currents from 5 kA to 50 kA (peak value) has been developed at LNE. The system relies on the use of non-invasif wideband (maximum 4 MHz) current sensors, of a 12 bits digitiser with a maximum sample rate of 100 Mega-samples per second and of a data acquisition and treatement software. The values of the expanded uncertainties (k = 2) are 1.4 mA·A−1 for the peak value and 15 ns·μs−1 for impulse current time parameters.

Key words

impulse current
8/20 μs wave
wideband current sensor
rogowski coil
tracability
uncertainty budget

Abstract

This paper describes the procedure recently introduced at LNE to calibrate low-voltage AC-DC transfer reference standards from 10 Hz to 1 MHz. Especially, a set of micro-potentiometers was developed in order to take into account the voltage level dependence of the standards during the step-down procedure. First measurement results are presented.

Key words

ac-dc difference
calibration
thermal converters
uncertainty
voltage measurement

Abstract

The kilogram is the last unit of the International System of Units (SI) still defined by an artefact, namely the International Prototype of the Kilogram (IPK). Comparisons carried out over 100 years between IPK, its official copies and national prototypes have revealed a mass change (in relative term) of five parts in 108. After a brief history of the unit of mass, this paper underlines the need to redefine the kilogram with reference to a fixed numerical value of a fundamental constant. It explains why the Planck constant h was chosen and gives the last results obtained with watt balance experiments nowadays able to link h to a macroscopic mass to within a few parts in 108. Finally, it proposes a possible route for the national metrology institute for the mise en pratique of the kilogram after its redefinition.

Key words

unit of mass
kilogram
redefinition of the kilogram
planck constant
watt balance