Electromagnetic wave absorbing properties of carbon‐rubber doped with ferrite

When ferrites are used for electromagnetic wave absorbers in the VHF and UHF bands we note their excellent properties such as their wider dynamic frequency bandwidth and their thinner thickness than that of lossy dielectric absorbers, which are due to their magnetic losses. However, there exists an upper frequency limit beyond which the frequency bandwidth of ferrite absorbers becomes narrower than that of lossy dielectric absorbers. In this paper we added ferrites to carbon‐rubbers and examined their characteristics as electromagnetic wave absorbers. We found through experiments that the relative bandwidth is widened more than twice by adding ferrites of only relative weight ratio 0.2 to rubber when the relative weight ratio of carbon to rubber is 1.1. Although we made measurements in the frequency range of 5 to 6 GHz, we expect the same effectiveness at higher frequencies.