Optimization of Performance Parameters of Doped Ferrite-Based Microwave Absorbers: Their Structural, Tunable Reflection Loss, Bandwidth, and Input Impedance Characteristics

In this study, M-type barium strontium hexagonal ferrite was prepared with CoSn doping. The crystallographic structure of ferrite compositions was explored using X-ray diffraction (XRD). The microwave absorption characteristics were investigated on a vector network analyzer as a function of the doping of Co2+ and Sn4+, frequency, and thickness of the samples. Analysis of measured XRD patterns confirmed the M-phase in the prepared samples. The electromagnetic parameters accompanied by permeability/magnetic loss, dielectric constant/loss, were increased with CoSn content. The obtained results revealed that microwave absorption was enhanced by doping with Co2+ and Sn4+ ions. The absorption was increased from -15.2 dB in compositions $x =0.0$ to -51.09 dB in $x =0.6$ composition; -10 dB bandwidth = 2.43 GHz was displayed in $x =1.0$ composition at 1.7 mm thickness. Both input impedance and $\lambda $ /4 criterion based on thickness doping govern the mechanism of microwave absorption. $x =1.0$ composition owes a large bandwidth to thickness ratio of 3.52 at the frequency of 10.88 GHz and a percentage bandwidth of 22.33 % at a thickness of 1.7 mm. The observed absorption peaks were tuned to the desired frequency by exploiting the composition thickness and input impedance through doping with Co2+ and Sn4+ ions. The wide bandwidth with optimized absorption find applications in the field of wireless communication such as isolators, circulators, and radar application.