Key facts
The R&S®NTS Series thermocouple power sensors are engineered to serve as RF power measurement standards. With their passive, analog-only design, the R&S®NTS family can be used as a microcalorimeter based primary measurement standard or as a secondary or transfer standard. A proprietary thermoelectric detector chip developed specifically for the NTS supports RF-DC substitution at the metrology grade level .
The R&S®NTS family has various models covering the frequency range from DC to 170 GHz.
Several NTS models are available with coaxial and waveguide RF connectors. All models have a high maximum input power of + 20 dBm, fast settling times and extremely flat frequency response.
RF primary and secondary standard solution for NMIs (national metrology institutes) and accredited calibration laboratories
Precision measurements are important in industrial quality assurance and are necessary for top-quality industrial production. Instruments must be calibrated in line with international standards for quality management systems (DIN EN ISO 9000) as well as product liability and environmental protection requirements. Test results are reliable only when they are made by calibrated instruments whose calibrations can be traced to national standards.
National metrology institutes are at the top of the calibration hierarchy and perform substitution measurements with primary measurement standards that trace RF power to the equivalent SI unit, DC power. The measurement is made inside a microcalorimeter to be as precise as possible.
Accredited calibration labs are the next level in the calibration hierarchy. The reference standards used in these calibration labs are calibrated by the national metrology institutes.
In all those applications, the substituted DC power can be measured with the customers own, well known commercial, off-the-shelf DC nanovolt meter with traceable calibration.
The calibration hierarchy
A modern thermoelectric power detector chip revolutionizes the traceability process
Reference standards must be passive and based on thermistors or comparable technology. Yet thermistor mounts have not been used for industrial RF power measurements for decades and the technology has not been developed further. Even though thermistor mounts have great long-term stability - which helps national metrology institutes keep them in working condition – fewer and fewer fully functional samples are available. New frequency bands are also not covered. The power standards are now obsolete because of a new generation of technology in the industry and defective standards can no longer be replaced .
R&S®NTS is a high-performing replacement that uses a modern thermoelectric power detector chip. The NTS is designed to easily replace thermistor mounts. The NTS is small enough to fit any microcalorimeter, requires no additional base units and connects directly to existing DC nanovolt meters. The substitution measurement workflow is similar to that for thermistors but with even better performance. Finally, a dedicated R&S application for direct comparison measurements can help with the transition.
Not only are R&S®NTS RF power standards new parts, but they also are more robust and modern than thermistor standards. Their tiny size and passive measurement method makes them ideal replacements for outdated thermistors. They replace legacy standards, but also cover new frequency bands and RF connectors, allowing commercialization of new frequency bands for current and future wireless communication standards, such as 6G.
Two R&S®NTS170TWGs mounted in a microcalorimeter experimental setup for traceable calibration using the DC substitution principle. The active sensor is supplied with a high-frequency signal, while the passive sensor serves as a reference. A differential temperature measurement in the millikelvin range uses a thermopile to determine the effective power sensor efficiency. © Physikalisch-Technische Bundesanstalt
Technological leap over thermistor technology based on proven R&S®NRP technology
Tracing RF power is an analog measurement, which always has a margin of error. Measurement equipment with the best available RF properties helps minimize such uncertainty.
Enter the R&S®NTS thermoelectric power detector chip. The technology was first used in R&S®NRP RF power sensors over two decades ago and has been continually improved with proven long-term reliability and stability.
The advanced transducer technology in the R&S®NTS was designed for the highest RF substitution measurement accuracy requirements. It has excellent matching and a flat frequency response for easy and reliable measurements. The technology also has
a high maximum power rating for wide overall dynamic range.
Two symmetrical RF and DC heaters inside the transducer create near-perfect RF-DC substitution.
Optimized transducer design ensures high linearity in substitution measurements, while the operating point influence on the calibration factor from the R&S®NTS was reduced to ppm per mW.
R&S®NTS sensors feature a 4-wire heater connection for current sourcing and voltage control
for precise measurements of substituted DC power.
The DC lines inside the NTS are optimized for low impedance to minimize heating loss outside the transducer.
R&S®NTS devices feature an additional internal temperature sensor to aid in correction. Even the tiniest temperature effects can be compensated to keep uncertainty to an absolute minimum and optimize settling times in the microcalorimeter.
R&S®NTS thermoelectric power detector chip
Thermoelectric power detector chip improves and shortens calibration cycle
Measurement points cost time, and time is money. R&S®NTS revolutionizes calibration workflows over thermistors by using their key thermoelectric power detector chip performance properties. The flat frequency response requires fewer measurement points while maintaining accurate calibration. High sensitivity results in a higher output signal for less noise and shorter measurement times. Lastly, the short settling time reduces the required measurement time per calibration point.
Frequency response curve: NTS vs. competition
Portfolio from DC to 170 GHz
The R&S®NTS family of RF power transfer standards currently has 5 coaxial models from DC to 67 GHz, including N, 3.5mm, 2.92mm, 2.4mm and 1.85mm RF connectors. NTS170TWG with its WR 6.5 waveguide connector already covers D band from 110 GHz to 170 GHz.
The R&S®NTS with modified RF reflection factors is also available as open, short, and mismatched standards for selected connector types. The special variants are used to determine the microcalorimeter correction factor.
All R&S®NTS models have a push-pull-connector for secure connections, compact size and low thermal mass.
An optional feature is device identification with the 1-Wire® protocol (passive in calibration mode) to help with automated calibration workflows.
R&S®NTSxT(WG) family of RF power transfer standards
R&S®NTS ensure self-sufficiency for RF traceability and calibration
RF measurement devices, whether RF Power Sensors, Signal Generators or others, must be regularly calibrated to comply with RF specifications.
The R&S®NTS has the tools for the RF power traceability required to calibrate RF measurement device amplitude. Customer no longer need RF amplitude calibration providers, such as accredited calibration labs or T&M equipment manufacturers.
Along with the R&S®NRPC calibration solution, R&S®NRP RF power sensors and a wide range of RF signal generators, Rohde & Schwarz has a full range of equipment for traceable RF calibration along the whole calibration hierarchy.
R&S®NTS RF power standards ensure adherence to the calibration pyramid hierarchy
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