[en] In this paper is presented a method to find the conditions of existence for anisotropic different plasmas which present the same reflection coefficient. The analytical dependence of the complex reflection coefficient on the plasma parameters wao examinated. Then the numerical calculations were made with the use of a computer. The results of these calculations have been plotted on a special diagram thus allowing the direct determination of the plasma parameters ωsub(p)/ω, ωsub(b)/ω, ν/ω with the reflection coefficient being known from measurements and on of the above mentioned parameters, or to establish what are the distinct sets of values for the plasma parameters ωsub(p), ωsub(b), ν for which the same reflection coefficient is obtained. The method also could be applied in two both cases of plasma explored by means of TEM mode and by guided waves respectively. (authors)