Connector Passive Intermodulation

Lightning Protection Information


Causes and cures.

Connector Passive Intermodulation

Intermodulation problems due to non-linearities have been a problem for a long time. With increasing demand for mobile communications, the need for greater channel capacity and more sensitive receivers have made Passive Intermodulation Distortion (PMD) more of a problem than ever.

There are many causes of PMD in a communications system. One that directly affects PolyPhaser and its products are connectors and connections to them. The following list was compiled from several articles on PMD.

Restrict connector materials to copper and copper alloys.

Connector body plating of silver or white bronze with a minimum plating thickness of 6u m (0.0002 in.).

Avoid use of stainless, nickel, or ferrite in signal path.

Quality machining - minimum finish of .4 mm.

Properly designed interface at connect, panel, and contact surfaces.

Avoid crimp connections - all connections should be soldered. Clamp and solder outer contacts for best static and dynamic performance.

DIN connectors are less susceptible to Intermodulation than N connectors.

Avoid hermetic seals containing Kovar.

Connectors used by PolyPhaser including 7/16 DIN are supplied with gold center contact pins.