Non-Contact Measurement Method for High Frequency Impedance of Load at the End of Wire Harness

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Event
WCX™ 17: SAE World Congress Experience
Authors Abstract
Content
To avoid a trial and error adjustment for designing EMI filters, clarifying load impedance of operating condition, i.e., dynamic impedance of equipment is very useful. Therefore the need to a non-contact measurement method of the impedance connected to a wire harness is increasing rapidly.
A measurement method using a network analyzer with two current probes was previously proposed. However, it was confirmed only up to 30 MHz. Many radio equipment operate above 30 MHz such as FM receivers and GPS receivers installed in vehicles. So increasing the measurement frequency is necessary in the auto industry.
At first, we tried to expand the applicable frequency to 100 MHz, i.e., FM band. In this study, we applied the transmission line theory using the non-contact measurement method. Furthermore, in order to use the theory, the characteristic impedance and phase constant of the wire harness are required. So we made an additional measurement to estimate them.
As a result, the load impedance was measured with a 10% error up to 100 MHz and the validity of the newly proposed measurement method was confirmed experimentally. Accordingly the possibility of an appropriate EMI filter design in the FM band was found.
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DOI
https://doi.org/10.4271/2017-01-1643
Pages
6
Citation
Tanaka, M., Oguri, Y., Iida, M., Yoshikawa, C. et al., "Non-Contact Measurement Method for High Frequency Impedance of Load at the End of Wire Harness," SAE Int. J. Engines 10(4):2034-2039, 2017, https://doi.org/10.4271/2017-01-1643.
Additional Details
Publisher
Published
Mar 28, 2017
Product Code
2017-01-1643
Content Type
Journal Article
Language
English