Rohde & Schwarz expands its portfolio of metrological reference solutions with the R&S NTS thermoelectric
RF power transfer standards. The new sensor family has been specifically developed for traceable RF power
measurements at the highest metrological level and positions itself as a modern replacement for increasingly
obsolete thermistor mount standards. Featuring a purely passive, analog design, R&S NTS sensors are
suitable both as primary standards in microcalorimeters and as transfer standards for national metrology
institutes (NMIs), accredited calibration laboratories and demanding industrial users.
Caption: With R&S NTS transfer standards national metrology institutes (NMIs) and accredited calibration
laboratories can easily modernize their existing RF power calibration solutions.
Precise power measurements are a fundamental requirement for high quality industrial production, quality
assurance and regulatory compliance. International quality management standards as well as product liability
and environmental protection requirements mandate that measurement equipment be calibrated regularly
and fully traceable to national standards. For decades, thermistor mount standards served as a reference for
traceable RF power. However, the development and manufacturing of new parts ended years ago. Hence,
neither replacement parts nor coverage of new frequency bands, such as D-band, are available.
Designed to replace obsolete thermistor standards
This is exactly where the R&S NTS product family from Rohde & Schwarz comes into play: it provides direct,
high-performance replacement for thermistor mounts. Its compact form factor fits seamlessly into existing
microcalorimeter setups without requiring additional base units. The sensors connect directly to commercially
available, traceably calibrated DC nanovoltmeters, allowing laboratories to continue using familiar
measurement workflows. At the same time, Rohde & Schwarz offers dedicated software support to simplify
the transition from thermistor-based standards to modern thermoelectric technology.
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Proven thermoelectric technology for metrology-grade accuracy
The thermoelectric power detector chip in R&S NTS was developed specifically for metrological RF-DC
substitution. Its technology builds on more than two decades of proven 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. Optimized 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 minimize uncertainty across the entire
operating range. A high maximum input power of +20 dBm and fast settling times further enhance usability in
precision calibration environments.
Additional design details underline the metrology focus: a 4-wire DC heater connection for precise power
substitution, low-impedance DC lines to minimize parasitic heating losses, and an integrated temperature
sensor to compensate even the smallest thermal effects. Moreover, 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 available to
support microcalorimeter correction factor determination. The product portfolio will continue to evolve, with
further models being added in the future.
With the R&S NTS RF power transfer standards, Rohde & Schwarz empowers 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 broad portfolio of RF signal generators, Rohde & Schwarz delivers a complete, end-toend ecosystem for traceable RF power calibration along the entire calibration hierarchy