Reduction of SWR and its effect on immunity to radiated electromagnetic interference

The technique of matching the input impedance of automotive electronic controller ports to that of the connecting cables is shown to achieve increases in immunity to unwanted radiated interference (standing wave ratio) over a wide frequency range. The amount of increase, on average, is of the order of 50 per cent. The additional components required are low in cost, suitable for automated assembly, occupy a minimum of printed circuit board area and are in general not subject to high tooling costs or single supply source restrictions.<>