A follow-up of this project started on 1st May 2023 with the title "Development of RF and microwave metrology capability II" (see the project webpage https://rfmwii.cmi.cz/). The project lifetime is 3 years (2023 - 2026). The project will be focused on topics not addressed in the 15RPT01 and will go beyond the state-of-the-art in several areas:
- Advanced RF power measurement techniques
RF power traceability at the primary level is provided using a calorimeter, which is only available in several developed NMIs. Moreover, calorimeter measurements become very cumbersome and expensive as the frequency increases above 50 GHz, and the technique is only available for power sensors based on a thermal conversion principle. In other cases, secondary-level techniques for the calibration of power sensors are used. Another commonly measured quantity is RF attenuation, however primary level attenuation measurements require traceable standards, which are limited to MHz frequencies. Measurement of attenuation at GHz frequencies and reliable measurement of high attenuations (>100 dB) is therefore problematic, particularly in less experienced NMIs. More affordable and practical techniques are therefore required. This project will establish capabilities for (i) the automatic measurement of RF power and assessment of the Monte Carlo simulation methods for the calculation of uncertainties, which will be validated by a comparison of direct RF power measurement, (ii) RF power measurement and power sensor calibration (calibration factor) using a vector network analyser (VNA), and (iii) the measurement of S‑parameters using VNAs and the measurement of attenuation using a spectrum analyser or another high‑dynamic range device
- Antenna measurements
Antenna measurements are very demanding due to the level of knowledge of the underlying principles of electromagnetic field theory, measurement equipment and laboratory facilities required. Although calibration of basic quantities such as antenna gain is well established in more experienced NMIs at frequencies up to tens of GHz using conducted tests (i.e., the antenna is generally connected to the analyser using a cable), currently there are significant challenges in the area of 5G communications for measurement of quantities over the air, i.e., without the use of cables. The project will (i) develop traceable methods for antenna calibrations in the frequency range 9 kHz – 40 GHz, (ii), investigate the advantages and disadvantages of different calibration techniques for antenna calibrations, (iii). validate the new capabilities for antenna calibration by intercomparisons, and (iv) produce a best practice guide on the calibration of antennas in different set ups.
- Electromagnetic field measurements
Electromagnetic field measurements are also very demanding and require considerable experience. Low‑frequency electric and magnetic field generation and measurements are available in some less experienced NMIs up to frequencies of tens of kHz, however, measurements at MHz or even GHz frequencies are currently offered only in more experienced European NMIs. The project will develop or improve capabilities for (i) electromagnetic field calibration in the frequency range from 10 Hz up to 40 GHz, including the generation of electromagnetic fields, and (ii) the measurement of electromagnetic field intensity, including reducing the causes of deviations between calibration results obtained from different realisations or different laboratories. The new capabilities for electromagnetic field generation and calibration will then be validated by intercomparisons. Finally, a best practice guide on how to build calibration capability for electric and magnetic fields over a full frequency range (i.e., 10 Hz – 40 GHz) will be produced. At the conclusion of the project, several less experienced NMIs will be able to build their own simple realisations of electromagnetic field intensity (parallel plate capacitor, Helmholtz coils, TEM cell) or utilise commercial solutions (fully anechoic chamber).