Changes In Cable Insertion Loss And Phase

By W. L.Gore & Associates

Insertion-loss tracking is the ability of different assemblies of the same type and length to closely reproduce their inherent loss characteristics with changing temperature. As with phase tracking, the closer the assemblies track, the lower the residual systemic error and the more consistent the beamwidth, sidelobe suppression, and beam steering. System range, jamming and clutter resistance, and overall accuracy are ultimately superior. Poor insertion-loss tracking is generally attributable to poor control over materials and processes during cable manufacturing or to using cable assemblies with different characteristics.

This curve is a property of bulk cable (0.190 in. diameter, solid center conductor, PFA jacket cable); very low loss cable assemblies may deviate slightly due to connector effects over temperature. Insertion-loss change is in percent dB relative to 0 dB change at 25°C. This measurement was taken at 18 GHz; it is a weak function of frequency and cable type. Insertion-loss change is primarily due to the change in conductivity of the silver with temperature. To a lesser extent, the loss tangent of the ePTFE is also a function of temperature.