Investigation of Intermodulation Products Generated in Coaxial Cables and Connectors.

Abstract

Abstract : This program was performed to investigate the parameters that may affect the generation of intermodulation (IM) products within typical coaxial cables and connectors. The parameters investigated include physical and material properties of the test components as well as electromagnetic properties of the applied signals. A repeatable measurement scheme capable of measuring very low level IM products was developed and evaluated. This test setup was used to measure the IM levels producted by 83 test samples selected to be representative of the coaxial cables and connectors employed on Command, Control, and Communications (C3) platforms. Mathematical models were developed which describe the IM behavior of these cables and connectors as a function of the various parameters investigated. In order to verify the cable-connector model, the IM levels of 21 additional test samples were predicted and then measured. The cable-connector combination model effectively predicts the IM levels within + or -4 dB as a function of each parameter except frequency; it predicts the variation with frequency to within 10 dB over the 20 to 450 MHz frequency range. (Author)