General Method for Characterization of Power-Line EMI/RFI Filters Based on S-Parameter Evaluation

• Published in: IEEE transactions on electromagnetic compatibility Vol. 58; no. 5; pp. 1465 - 1474
• Main Authors: Haase, Martin, Hoffmann, Karel, Hudec, Premysl
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-10-2016; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Automation; Cascades; Common mode (CM); differential mode (DM); Electromagnetic interference; electromagnetic interference (EMI) filter; Frequency measurement; IEEE standards; Impedance; Impedance measurement; impedance tuner; information security; Insertion loss; Interference; Measurement methods; Microwave filters; Microwave measurement; power-line filter; radio-frequency interference (RFI) filter; Scattering parameters; Spectrum allocation; Transmission line measurements; Unknown environments
• ISSN: 0018-9375; 1558-187X
• DOI: 10.1109/TEMC.2016.2583221

This paper deals with a general working approach for determining the lowest possible insertion loss of power-line interference filters in their stop bands at high megahertz or gigahertz frequencies. It is shown that at these frequencies, the measurement methods recommended for testing of interference filters in available standards for frequencies up to 1 GHz fail in determining their lowest possible insertion loss. This problem is solved by the newly developed method which also enables the characterization of concerned filters in a completely impedance unknown environment. It is based on two-port vector network analyzer measurement and postmeasurement data processing applying an impedance matching technique. Experimental verification of the new method using two Maury Microwave automated tuners and a cascade of low-pass coaxial filters was performed in the frequency band from 6 to 12 GHz. The results show that measurement-evaluation procedures performed according to the newly developed method provide more reliable and precise results when compared to measurement procedures corresponding to methods described in common standards. The new method was also applied to the characterization of a professional EMI/RFI filter from 1 to 10 GHz.