Ferromagnetic microwires are widely used in ultrahigh frequency equipment. A system based on the vector network analyzer ZVA-67, which makes possible to measure the ferromagnetic resonance parameters of microwires in the frequency range from 0.1 to 14 GHz is proposed. Impedance of CuBe / FeCoNi and CoFeSiB microwires is approximated by component values of the main diagonal of the magnetic susceptibility tensor. The proposed method makes possible to understand interesting features of the electromagnetic properties of the microwires in those regions of frequencies and magnetic fields where the ferromagnetic resonance is observed.