4–18 GHz Reconfigurable Rasorber with Grating Lobe Suppression Using Absorptive Honeycombs

This paper presents a reconfigurable rasorber covering the 4–18 GHz range, utilizing absorptive honeycombs to effectively suppress high-frequency grating lobes. Building on a previous three-layer frequency selective rasorber (FSR) operating in the 1–7 GHz band, we introduce a dual-layer honeycomb structure with tunable dielectric properties achieved through carbon fiber doping. The proposed configuration exhibits low-pass and high-stop transmission characteristics, efficiently absorbing high-frequency waves while maintaining a low-frequency bandpass window. Compared to earlier designs constrained by pin diodes operating frequency limitations in radar applications, the new configuration offers improved absorption performance and broader frequency coverage, making it suitable for advanced electromagnetic (EM) interference suppression and radar cross-section reduction.