Improvements on the MTL-STD-85485 low pass cable line

Abstract

MIL-STD-85485 describes low-pass cables suppressing conducted and radiated RFI by dielectromagnetic absorption: the basic specification of such cables is indeed an attenuation of 100 dB/m or more, in the frequency range 1 GHz-18 GHz. There is a need to update this standard, issued in 1981: indeed there are current requests for "stopband frequencies" over 18 GHz, and/or requests for pass-band frequencies, higher than 10 MHz. The article describes the concept and implementation of such performance, which cannot be related anymore exclusively to magnetic absorptions, as concomitant to the physics of ferri and/or ferromagnetic materials.