An ultrawideband conducted emission Direct-Coupling Probe calibration method

Conducted emission (CE) measurement is essential to integrated circuit (IC) electromagnetic compatibility (EMC) testing, and accurate calibration of testing equipment is the prerequisite for the reliability of IC CE measurement. This paper proposes an ultrawideband Direct-Coupling Probe (DCP) calibration method. It can effectively improve the deficiencies of the calibration method described in standard IEC 61967-4. Impedance matching calibration fixtures were developed, and a de-embedding algorithm based on time domain reflectometry (TDR) and microwave scattering parameter measurement was proposed. This method can theoretically extend the calibration frequency range of DCP to 20 GHz. The experiment verifies the combination of the algorithm and fixtures can effectively suppress the reflection and ripple caused by the impedance mismatch between the instrument system and DCP and improve the accuracy and repeatability of the measurement process. Factors affecting calibration results, such as fixture characteristic impedance, grounding, and time window selection, are also analyzed and discussed. •Proposes an ultrawideband direct-coupled probe calibration method up to 20 GHz.•Designed impedance transformation fixtures for direct-coupling probe calibration.•Proposing innovative ultrawideband de-embedding algorithms for calibrated fixtures.•Effectively suppresses reflection and ripple in high-frequency calibration.•Analyzed the effects of fixture characteristics, grounding, etc., on calibration results.