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Carbon fiber cloth/epoxy resin composites with different layer orientation angles were prepared to evaluate electromagnetic shielding properties in the X band. The results showed that the electrical conductivity, dielectric constant and shielding effectiveness of composites decreased with increase in layer angle. Absorbed power had the maximum value (0.577) at 49.60° with sample thickness 4.00 mm. After using carbonyl iron powder as the radio wave absorber, both conductivity and shielding effectiveness improved when layer angle was beyond 10.06°. Reflected power decreased while absorbed power increased with increase in layer angle and their variation rates decreased. Structure and function integrated shielding products made of these composites can be used to get the highest shielding effectiveness or highest absorbed power with designed layer angles. [ABSTRACT FROM AUTHOR]

Carbon fiber felt–glass fiber felt/epoxy resin multilayer composites with different layer angle were prepared to evaluate electromagnetic shielding properties in the X band. Comparison of composites with or without adding carbonyl iron powder was made in electric properties and shielding properties. Carbon fiber felt–glass fiber felt/epoxy resin multilayer composite can get a high shielding effectiveness (76.3 dB) at a suitable thickness (4.00 mm) when layer angle is close to 0°. Shielding effectiveness decreases rapidly with increase in layer angle and power constituent parts have different variations. Variations in dielectric constant and magnetic permittivity were found after adding carbonyl iron powder. Use of carbonyl iron powder can improve shielding effectiveness and absorbed power when layer angle is beyond 35°. Carbonyl iron powder-carbon fiber felt–glass fiber felt/epoxy resin composite can get high absorbed power (62.6%) when layer angle is about 45°. [ABSTRACT FROM AUTHOR]