On contact conditions in connectors to cause Common Mode radiation

When contact failure occurs in a connector in a coaxial HF signal transmission line, common mode (CM) radiation occurs on the line. We focus on contact conditions in a connector causing CM radiation. The experiments and the simulations verified that the CM radiation increases as contact resistance increases. While the CM current greatly depends on the pattern of distribution of contact resistance at a low resistance, the CM current does not depend on it at a high resistance. It is necessary to keep a distribution of four or more contact spots symmetrical.