Publications
Statistical characterization of multi-conductor cables using large numbers of measurements
Understanding and characterizing the electrical properties of multi-conductor shielded and unshielded cables is an important endeavor for many diverse applications, including airlines, land based communications, nuclear weapons, and any piece of hardware containing multi-conductor cabling. Determining the per unit length capacitance and inductance based on the geometry of the conductors, number of conductors, and characteristics of the shield can prove quite difficult. Relating the inductance and capacitance to shielding effectiveness can be even more difficult. An exceedingly large number of measurements were taken to characterize eight multi-conductor cables, of which four were 3-conductor cables and four were 18-conductor cables. Each set of four cables contained a shielded cable and an unshielded cable with the inner conductors twisted together and a shielded cable and an unshielded cable with the inner conductors not twisted together (or straight). Male LJT connectors were attached on either end of the cable and each cable had a finished length of 22.5 inches. The measurements performed were self and mutual inductance, self and mutual capacitance, and effective height. For the 18 conductor case there ended up being an 18 by 18 element matrix for inductance (with the self inductance terms lying on the diagonal) and an 18 by 18 matrix for capacitance. The effective height of each cable was measured over a frequency range from 220 MHz to 18 GHz in a Mode-Stirred Chamber. The effective height of each conductor of each cable was measured individually and all shorted together, producing 19 frequency responses for each 18 conductor cable. Shielding effectiveness was calculated using the effective heights from the shielded and unshielded cables. The results of these measurements and the statistical analysis of the data will be presented. There will also be a brief presentation of comparison with numerical models.