Abstract: An object is to provide a ?/4 radio wave absorber that includes a support, a resistive film, a dielectric layer, and a reflective layer, and that has higher radio wave absorption performance. The object is achieved by a ?/4 radio wave absorber that includes a support, a resistive film, a dielectric layer, and a reflective layer, and that satisfies formula (1): ?0.375x+1086.9<y<?0.375x+1140 wherein x represents a resistance value of the resistive film, and y=the thickness of the support×(the relative permittivity of the support)0.5+the thickness of the dielectric layer×(the relative permittivity of the dielectric layer)0.5.

Abstract: An object of the present invention is to provide a radio wave absorber having excellent radio wave absorption against oblique incidence, particularly against oblique incidence of radio waves at around 79 GHz. The object can be achieved by a radio wave absorber having characteristic A: an absorption range with absorption performance of 15 dB or more within the frequency band of 75 to 85 GHz of 4 GHz or more in a TM polarization measurement at 45° incidence and/or characteristic B: an absorption range with absorption performance of 15 dB or more within the frequency band of 75 to 85 GHz of 4 GHz or more in a TB polarization measurement at 45° incidence.

Abstract: An object of the present invention is to provide a radio wave absorber that has excellent radio wave absorption against oblique incidence, particularly against oblique incidence of radio waves at around 60 GHz. The object can be achieved by a radio wave absorber that has an absorption range with absorption performance of 15 dB or more within the frequency band of 55 to 65 GHz of 4 GHz or more in a circular polarization measurement at 45° incidence.

Abstract: A conductive nonwoven fabric comprising a metal layer on at least one surface thereof, the conductive nonwoven fabric having a sheet resistance of 200 to 600 ?/? and a density of 2.0×104 to 8.×105 g/m3. The conductive nonwoven fabric has higher radio wave absorption properties (high absorption and low reflectivity), even against high-frequency radio waves.

Abstract: An object is to provide a ?/4 radio wave absorber that includes a support, a resistive film, a dielectric layer, and a reflective layer, and that has higher radio wave absorption performance. The object is achieved by a ?/4 radio wave absorber that includes a support, a resistive film, a dielectric layer, and a reflective layer, and that satisfies formula (1): -0.375x+1086.9<y<?0.375x+1140 wherein x represents a resistance value of the resistive film, and y=the thickness of the support×(the relative permittivity of the support)0.5+the thickness of the dielectric layer×(the relative permittivity of the dielectric layer)0.5.

Abstract: The present invention aims to provide a ?/4 type radio wave absorber having excellent durability. Provided is a ?/4 type radio wave absorber including: a resistive film containing molybdenum; a resistive film; a dielectric layer; and a reflective layer, in the stated order.