In this work we have studied the influence of ТiO2 and Bi2O3 doping admixtures and impurities on the microstructure and properties of radio-absorbing Mg-Zn ferrites. The morphological peculiarities of inclusions of these admixtures in a ferrite ceramics are established. It is shown that the use of doping admixtures and impurities of these oxides makes it possible to control the frequency dependences of the magnetic permeability and dielectric permittivity of Mg-Zn ferrite materials. Examples of controlling the absorption spectra in a radio frequency range through variations in the composition of given radio-absorbing materials are presented.