Rohde & Schwarz has introduced the R&S NTS thermoelectric RF power transfer standards to its portfolio of metrological reference solutions
The new sensor family has been developed for traceable RF power measurements at the highest metrological level and positions itself as a modern replacement for increasingly obsolete thermistor mount standards.
Its purely passive, analogue design makes R&S NTS sensors suitable as primary standards in microalorimeters and as transfer standards for national metrology institutes (NMIs), accredited calibration laboratories and demanding industrial users.
Precise power measurements are a fundamental requirement for high-quality industrial production, quality assurance and regulatory compliance. International quality management standards, product liability, and environmental protection requirements mandate regular calibration of measurement equipment and full traceability to national standards.
For decades, thermistor mount standards have acted as a reference for traceable RF power, but the development and manufacturing of new parts ended years ago. As a result, neither replacement parts nor coverage of new frequency bands, such as D-band, are available.
Designed to replace obsolete thermistor standards
The R&S NTS product family is designed to provide a direct, high-performance replacement for thermistor mounts. Its compact form factor fits seamlessly into existing microcalorimeter setups without additional base units.
The sensors connect directly to commercially available, traceably calibrated DC nanovoltmeter, enabling laboratories to continue using familiar measurement workflows. Rohde & Schwarz also offers dedicated software support to simplify the transition from thermistor-based standards to modern thermoelectric technology.
Proven thermoelectric technology for metrology-grade accuracy
The thermoelectric power detector chip in R&S NTS was developed for metrological RF-DC substitution. Its technology builds on more than two decades of Rohde & Schwarz experience with R&S NRP power sensors, refined for the highest accuracy requirements.
The transducer features two highly symmetrical RF and DC heaters that ensure near-perfect RF-DC substitution. Optimised heater design delivers excellent linearity, with operating-point influence on the calibration factor reduced to the PPM-per-milliwatt range.
Outstanding RF properties such as excellent impedance matching and an extremely flat frequency response reduce uncertainty across the entire operating range. A high maximum input power of +20dBm and fast settling times further improve usability in precision calibration environments.
Additional design details highlight the metrology focus: a 4-wire DC heater connection for precise power substitution, low-impedance DC lines to reduce parasitic heating losses, and an integrated temperature sensor to compensate for small thermal effects. All models feature a robust push-pull DC connector, low thermal mass and optional electronic device identification for automated calibration workflows.
A complete solution for the calibration hierarchy
At launch, the R&S NTS family includes multiple coaxial models from DC to 67 GHz and a waveguide model up to 170 GHz with a WR-6.5 connector. Special open, short, and mismatched variants are also available to support microalorimeter correction factor determination. The product portfolio will continue to evolve, with further models set to be added in the future.
With the R&S NTS RF power transfer standards, Rohde & Schwarz enables users to establish and maintain RF power traceability in-house. Combined with the R&S NRPC calibration solution, R&S NRP RF power sensors, and a portfolio of RF signal generators, Rohde & Schwarz provides a complete, end-to-end ecosystem for traceable RF power calibration along the entire calibration hierarchy.
