The Danger of Intermodulation Generation by RF Connector Hardware Containing Ferromagnetic Materials.
Abstract
This technical memorandum is presented in advance of formal reporting on the in-depth study of mechanisms and means for reducing intermodulation generation (IMG) in passive radio frequency (RF) hardware, presently under way at the Naval Research Laboratory (NRL). It is imperative that the communication community be again and quickly alerted to the harmonic and IMG interference danger of RF connectors and associated components which contain ferromagnetic materials (iron, nickel, cobalt, and their alloys). In a recent search for improved RF connector designs it became evident that the body structure of many of the newer type coaxial connectors and adapaters are being manufactured from stainless steel, type 303, a low permeability (<2) ferromagnetic alloy. That such a material could be considered for fabricating RF connectors is difficult to understand because of the known non-linear effects of even small quantities of ferromagnetic contaminants in RF systems. To cut cost, nickel plating, another ferromagnetic material, is apparently also being widely substituted for previously used silver or gold plating of brass stock connectors. If satellite or other weak desired signal communication systems (utilizing multicarrier transmitters) are to succeed and/or survive, such interference generating materials must be eliminated in all transmission elements of the systems. To reverify the ferromagnetic threat and establish the magnitudes of interference, IMG tests of sample RF coaxial hardware were undertaken using the NRL IMG test facility.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 16, 1975
- Accession Number
- ADA061500
Entities
Organizations
- United States Naval Research Laboratory