Planar RF microstrip attenuators based on carbon black and exfoliated graphite powders

This paper presents a unique and modest design of microstrip attenuators based on N774 grade carbon black and exfoliated graphite powders. The required amount of attenuation is achieved by coating a layer of carbon black or synthesized exfoliated graphite on an etched section of the microstrip line. The proposed planar microstrip attenuators are designed, fabricated and tested over 3-5 GHz. The measured insertion loss of the proposed attenuators are found to be in the range of 7-10 dB for the N774 grade Carbon black, and 8-11.5 dB for the exfoliated graphite, respectively.