Preparation of radar absorbing materials with broad bandwidth by mixing carbonyl iron and FeSiAl particles

In order to increase the absorbing ability in the lower band (1-4 GHz) and expand the absorbing bandwidth, carbonyl iron and FeSiAl particles were established as absorbers, and wax as adhesive, and the electromagnetic parameters were tested by using a vector network analyzer, then the absorbing properties were calculated with a given thickness (0.5 or 1 mm). The results showed that both the complex permittivity and permeability increase as the ratio of quality increase. And under the same ratio of quality, FeSiAl particles has excellent absorbing properties in low frequency band (-6.8-1.2 dB), while inferior to carbonyl iron (-16.0-10.1 dB) in high frequency band (14-18 GHz). After mixing the two types of particles, the content of FeSiAl particles is adjusted, and a composite absorbers with good absorbing properties in low frequency band (-4.5-1.1 dB) and wide absorbing bandwidth (less than -4 dB in 3.8-18 GHz) is found. It has an instructive value to mix other excellent low frequency absorbers and high frequency absorbers to get materials in a wide absorbing band.