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Best paper award for PTB publication on radio frequency power measurements

13.04.2022

The authors Rolf Judaschke, Mathias Kehrt, Karsten Kuhlmann and Andreas Steiger receive the "Andy Chi Best Paper Award" for publishing the results of their two-year collaboration "Linking the Power Scales of Free-Space and Waveguide-Based Electromagnetic Waves". This prestigious award recognizes the best paper published in the “IEEE Transactions on Instrumentation and Measurement” in the past year and will be presented to the authors in person at the I2MTC 2022 conference.

 

In their paper, the authors were able to show that the two power scales of spectral response in free space and in waveguide in the WR-10 band (i.e., for frequencies from 75 GHz to 110 GHz) agree within their combined uncertainties.

 

For this comparison, a special measuring setup has been developed. It consists of a tailor-made, large elliptical mirror which focuses the radio frequency (RF) power, radiated by a special corrugated horn antenna, into the aperture of a free-space detector. Due to the different traceability of the two scales to the International System of Units SI, the comparison was of particular interest. On the one hand, the metrological traceability of the RF power in the waveguide is performed by direct substitution of the thermal equivalent with a DC power in a special WR-10 calorimeter at room temperature. On the other hand, the unique large-area and spectrally flat pyroelectric thin-film-detector (PTFD) used in the free space was previously calibrated at 1.4 THz. The terahertz (THz) detector standard used for this calibration is traced back through an electrical substitution radiometer with a cryogenic cavity absorber in the optical spectral region at a visible laser frequency.

 

This proof of equivalence opens the promising possibility of accurately measuring RF power in higher-frequency waveguide bands up to the THz range with the free-space method applied.

 

Quasi-optical measurement setup for the determination of the insertion loss between the waveguide plane A and the plane of the pyroelectric detector B consisting of input and output waveguides, corrugated horn antennas and elliptical mirrors.

Figure 1: Quasi-optical measurement setup for the determination of the insertion loss between the waveguide plane A and the plane of the pyroelectric detector B consisting of input and output waveguides, corrugated horn antennas and elliptical mirrors.

 

Photograph of the measurement setup with PTFD pyroelectric detector and reference waveguide power sensor.

Figure 2: Photograph of the measurement setup with PTFD pyroelectric detector and reference waveguide power sensor.

 

 

Contact persons:

·             Rolf Judaschke
Opens internal link in current windowDepartment 2.1 "Direct Current and Low Frequency"
   Rolf.Judaschke(at)ptb.de

·             Karsten Kuhlmann
Opens internal link in current windowDepartment 2.2 "High Frequency and Electromagnetic Fields"
   Karsten.Kuhlmann(at)ptb.de

·             Andreas Steiger
Opens internal link in current windowDepartment 7.3 "Detector Radiometry and Radiation Thermometry"
   Andreas.Steiger(at)ptb.de