Novel nanocomposites of reduced graphene oxide (rGO)–Fe ₃ O ₄ (rGO:IO), and nitrogen doped rGO–ε-Fe ₃ N (NrGO:IN) with unique ‘particle shielded by sheet’ morphology is reported for enhanced electromagnetic shielding effectiveness.

A triband band-stop spatial filter shield using frequency selective surface is designed and analyzed to block GSM 900, 1800, and Wi-Fi 2400 MHz frequency bands. Three constituent resonant elements exhibiting stop-bands are two Jerusalem cross (JC) elements with tortuous main arms, and a 45° rotated JC. The proposed unitcell is compact with size 0.078λ ₀ x 0.078λ ₀ , where λ ₀ is the wavelength of lowest resonant frequency in free space. An equivalent circuit model is developed to understand the behavior of its constituent elements. The proposed design offers better miniaturization and stable frequency response for up to 60° of incidence angle for both TE and TM polarizations, as compared to the earlier reported designs in the bands mentioned previously. Shielding effectiveness is verified with measurements in an anechoic chamber.

The shielding effectiveness (SE) of a metallic enclosure with double-layer frequency selective surface (DLFSS) has been calculated using a transmission line theory-based analytical formulation. The DLFSS layer placed on the front and back sides of the enclosure consists of a Greek cross aperture array. The equivalent circuit method and an empirical method are used to calculate the impedance of the Greek cross FSS. Then, the SE is calculated for various incidence and polarization angles. Calculated results are compared with the measured and numerical simulation results.

In this letter, a 2-layer thin wideband circuit analog absorber based on the concept of multiple resonances is realized with a thickness close to Rozanov's theoretical thickness. The absorber consists of circular loop arrays loaded with lumped resistors on FR4 substrate, backed by a metal plane, with a thickness of 0.40 λ _center (wavelength at the center frequency). The absorber offers 149% fractional bandwidth under normal incidence with a 10-dB reflectivity reduction in the frequency band of 3.6–24.6 GHz (C, X, Ku, and K bands). The structure is angularly stable for incidence angles up to 50° and 40° for TE and TM polarization, respectively. To analyze the resonances of the absorber, an equivalent circuit model is developed, and the results agree with the full-wave simulation. The designed absorber is validated with the measurements.