Connector Design Techniques to Avoid RFI.
Abstract
A paper, presented at the Ninth Connector Symposium, gave detailed experimental evidence of the serious RFI levels produced by commonly available RF connectors which use ferromagnetic materials (iron, nickel, cobalt or their alloys) for electrical conductors. For example, the body structure of a wide variety of precision made coaxial connectors and adapters are currently manufactured only from stainless steel, type 303, a ferromagnetic alloy. To cut cost and provide a corrosion resistant finish, nickel plating, another ferromagnetic material, has been almost exclusively substituted for silver or gold, previously employed to plate brass stock connectors. That such materials could be considered for electrical conductor service is difficult to understand because of the known nonlinear effects of even minute quantities of ferromagnetic contaminants in RF systems. Use of ferromagnetic materials, however, has become so widespread that silver or gold plated brass (nonferromagnetic) devices, which had been standard for many years, are no longer readily available as 'off-the-shelf' items but must be specially ordered in quantities (500 or more) to obtain reasonable production cost. Connectors fabricated from ferromagnetic materials typically produce IMG power levels 3 to 5 orders (1000 to 100,00 times) higher (worse) than without. Obviously such interference levels cannot be tolerated in todays highly sensitive communication systems. The ferromagnetic connector RFI problem came to light in 1975 during the Naval Research Laboratory's investigation of passive component nonlinearity and means for its reduction required by the Fleet Satellite Communications (FLTSATCOM) system, then under development.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 07, 1980
- Accession Number
- ADA088769
Entities
People
- Charles E. Young
Organizations
- United States Naval Research Laboratory