Lightweight, space efficient low-pass radio-frequency interference filter modules for bolometric detectors

Abstract

Extremely lightweight and space efficient low-pass radio-frequency interference (RFI) filter modules have been developed and tested for use with bolometric detectors. These filters are based on the compactness of a surface mount electro-magnetic interference chip filter. We have produced densely packed modules containing 21 filtered lines, which weigh 60 g, with dimensions of 38×36×11 mm. These modules provide greater than 20 dB attenuation over the entire frequency range tested (50 MHz–10 GHz) while providing over 60 dB attenuation for frequencies greater than 4.5 GHz. The filters suppress rf voltage noise and prevent radiation from RFI on the lines from entering the detector environment and heating up the bolometers. Modules have been used on bolometric detector systems containing as many as 16 RFI filtered bolometers.