A. A. Savin - Ph.D. (Eng.), Associate Professor, Radio Systems (RTS), Tomsk State University of Control System and Radio Electronics. E-mail: saasavin@mail.ru
V. G. Guba - Deputy chief metrologist, Micran, Researdh&Production Company, Tomsk. E-mail: vovg@micran.ru
G. N. Glazov - Senior Research Scientist, Micran, Researdh&Production Company, Tomsk. E-mail: gng@micran.ru

In this paper we present the simple and convenient mathematical method to calculate electric parameters of devices based on cascade connection of coaxial lines. Devices are using in modern microwave technology. This is due to such advantages of coaxial lines as ease of technical implementation, high reliability, low loss per unit length, wide frequency range, the simplicity of the theoretical calculation, etc. We have received ratios for calculation of scattering matrix and transfer matrix of small losses coaxial line and arbitrary characteristic impedance, also ratios for calculation of scattering matrix and transfer matrix of impedance discontinuity, The computation of impedance discontinuity parameters have done along with calculation of step capacitance. Mathematical model of Beatty standard used for vector network analyzer verification has reviewed in detail. Beatty Standard is an air coaxial line with inner conductor which consists of three concentric cylindrical sections of different diameter with axial symmetry and the transverse plane of reflection. Beatty Standard consists of a 50 Ohm air line that contains 25 Ohm line section. Beatty standard parameters are different from all of the calibration standards used in modern calibration kits. So it can be used at verification procedure. To compute Beatty standard scattering matrix, precision measurements of geometric dimensions have done. Then we have measured S-parameters of standard in 7 mm coaxial airline and have compared results. Measurements have performed using both Agilent Technologies, Inc. and Micran, Research & Production Company vector network analyzers. Computational analysis has revealed instruments provide its specification transmission and reflection parameters. In particular, vector-s modulus of difference results increases slightly with changing frequency, but not higher than minus 40 dB.