Non-contact measuring method for high-frequency impedance of load at the end of wire harness

Request to non-contact measurement method of load impedance connected to a wire harness is increasing rapidly. A method using network analyzer together with two current probes were previously proposed for this purpose, but it is valid only to 30 MHz. In this study, we extended the above-mentioned non-contact measurement method to 100 MHz by applying transmission line theory to the wire harness. The validity of the newly proposed measurement method was confirmed experimentally, and as a result the load impedance was measured with an error within 10% up to 100 MHz.