Dielectric Characterization of Heterogeneous Composite Fused Lightweight Perforated Microwave Absorber

This research presents a detailed dielectric characterization of a unique lightweight and broadband circular perforation-filled microwave absorber (PFMA). The PFMA unit cell is constructed by combining a dielectric substrate with synthesized carbon nanotubes (CNTs) and micrometer-sized titanium-dioxide (TiO2) particles, resulting in a heterogeneous composite structure. The structural coupling of these materials with an FR-4 dielectric substrate brings about significant alterations in dielectric properties and microwave absorption capabilities. The fabricated PFMA exhibits remarkable performance, with a wideband absorption bandwidth (BW) extending to 4.2 GHz in the X-band and achieving an absorptivity of over 90%. Notably, this absorbing structure is characterized by its compactness, with a thickness of just 2.7 mm, equivalent to $\lambda $ /11 of the center frequency. This work highlights the potential for a cost-effective solution in developing lightweight and broadband microwave absorbers (MAs), particularly beneficial for applications in stealth technology and beyond.