It is well known that there is no single measurement method for determining the modulus and phase of the complex transfer coefficient of two-port networks in the range of high and microwave frequencies. For definition of these quantities in the specified range of frequencies it is necessary to use a number of measuring devices working on different principles and providing far from equal accuracy of measurements. This diminishes the value of the measurement results and the possibility of their use, for example, for determining the dielectric constants of materials.