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.