Preparation and characterization of carbonyl iron/glass composite absorber as matched load for isolator

► Carbonyl iron/glass composite absorbers are prepared by pressureless sintering. ► Composite absorbers are difficult to densify and the minimum porosity is 13.08%. ► Composite absorber sintered at 520 °C for 40 min possesses highest bending strength. ► The initial oxidation temperature of carbonyl iron/glass absorber is about 400 °C. ► Absorber with a thickness of 1.25 mm shows a good absorption property in 8-12 GHz.