Wideband and Narrowband Microwave Characteristics of Co/Ti-Substituted M-Type Ca-Hexagonal Ferrite

Polycrystalline M-type CaCo (x) Ti (x) Fe(12-2x)O19 (x = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6) hexagonal ferrite compositions, with substitution of Co2+ and Ti4+ ions, have been synthesized by a two-route ceramic method. Vector network analysis was used to measure various microwave and electromagnetic parameters from 8.2 GHz to 12.4 GHz. The microwave shielding effectiveness (SE) due to absorption (SEA) and reflection (SER) was investigated based on S-parameters for the near field, and intrinsic parameters, accompanied by AC conductivity and skin depth, for the far field. The shielding effectiveness was primarily governed by absorption (SEA), and substitution of Co2+ and Ti4+ ions resulted in near- and far-field SEA of 54.85 dB at 10.49 GHz and 63.43 dB at 1.15 (Omega m)(-0.5), respectively, for the composition with x = 0.6. The AC conductivity exhibited a monotonic increase with frequency, whereas the skin depth decreased with frequency for all the compositions. The composition with x = 0.6 exhibited a 20-dB wide absorption bandwidth (WAB) of 3.67 GHz and 3.66 GHz for near and far field, respectively. The composition with x = 0.3 showed a 10-dB narrow absorption bandwidth (NAB) of 80 MHz for the far field.