New technologies in the health, energy, security, environmental, industrial and communication sectors require novel RF&MW devices and measurement methods which currently are under research and development (R&D). However, this R&D brings new challenges to the underpinning metrology for RF&MW as it requires advanced technologies.
Scattering parameter (S-parameter) measurements, RF power measurements and EMC tests and calibrations are important areas in RF&MW metrology and are used to ensure and increase product quality and end user confidence. For example, S-parameters are one of the essential parts of high frequency design and are used in the characterisation and modelling of linear RF&MW devices and systems. The reliability of S-parameter measurements depends on how well the characterisation and modelling of RF&MW components is performed, therefore, the devices used for this need to be calibrated accurately and their measurement uncertainty must be calculated precisely. However recent R&D has shown that the simplified characterisation and modelling approach that is currently used for RF&MW components is inadequate.
Most high frequency electronic devices include short distance communication units which generate low-power (P < 0.01 mW). In order to obtain traceable and accurate measurements at low-power in RF&MW metrology, power sensors, which are used for low-power measurements must be characterised accurately. However, during the characterisation of power sensors used for low-power measurements, the effect of each measurement parameter, especially the effects of harmonics at the output of signal generators, must be considered. Due to the difficulty of characterising harmonic effects, some less developed national metrology institutes (NMIs) ignore the effect of higher harmonics in low-power measurements and they are not able to characterise power sensors for low-power.
There is also a problem with RF&MW high-power measurements (P > 1 W) used in long distance communication, broadcasting radar applications and other applications. Characterisation of high-power measurement equipment such as wattmeters is generally performed using an ‘attenuator and power sensor’ combination in which both are calibrated at mid-power level (0.01 mW < P < 1 W). The characterisation parameters of both the attenuator and power sensor should be at the same power levels, however, this assumption does not describe the actual situation.
EMC is the interaction of electrical and electronic equipment with the electromagnetic environment, and other equipment. In order to avoid EMC related issues electronic goods manufacturers must test that their products are electromagnetically compatible with relevant regulations. However, new verification methods are needed to increase the quality of EMC test/calibration and measurements, in particular advanced verification methods using vector network analysers (VNAs). The development of new verification methods is also important for raising awareness of any problems before starting tests (i.e. just-before-test). Moreover, current knowledge between EMC and RF&MW laboratories is very weak, which reduces awareness in measurements/calibrations and, therefore the overall quality of both EMC and RF&MW measurements.
Most of the NMIs participating in this project have had to decline requests to perform measurements in RF&MW from stakeholders due to a lack of knowledge and/or experience in these areas. Therefore there is a strong need to improve the abilities of these European NMIs. The gap between developed and currently developing countries is growing constantly and this situation is even more pronounced for RF&MW metrology where not only knowledge and expertise are required, but also experience. In order to prevent further widening of this gap in RF&MW metrology, the knowledge and expertise of the more developed NMIs needs to be transferred to those NMIs with less experience. This sharing of knowledge and skills would help to strengthen the European RF&MW metrology network and would support a better and more effective cooperation between European NMIs. It would also ensure a joint effort from European NMIs on the big challenges in RF&MW metrology and would support future collaborations.
This is a joint research project carried out in the framework of the European Metrology Programme for Innovation and Research (EMPIR) (see:http://www.euramet.org/research-innovation/empir/). The EMPIR initiative is co-funded by the European Unions's Horizon 2020 research and innovation programme and the participating states. METAS is one of the project partners in the Project.
