Monitoring the parameters of printed strip lines in the microwave range of electromagnetic waves

Abstract

The characteristic impedance of printed strip lines is determined by their design, cross-sectional geometry, relative permeability of the insulating base, and other factors that cannot be accurately estimated. The known methods for monitoring its frequency dependence using microwave measurements are not perfect and require further development. The proposed work proposes a method for experimental monitoring of the entire set of parameters of printed strip transmission lines: wave impedance, relative effective dielectric constant, as well as phase velocity and attenuation coeffi cient of a propagating electromagnetic wave. The characteristic impedance is determined by the s-parameters of the connection of coaxial strip junctions with a segment of an electrically long line. The wave parameters measured in the coaxial channel are transformed in the area of contact of the coaxial and strip lines, which makes it possible to obtain an analytical estimate of the wave impedance over the entire frequency range of the vector network analyzer or at least in its individual frequency windows. In the proposed method, the phase velocity, attenuation coeffi cient and relative effective dielectric constant are controlled by the differential-phase method based on the results of measuring the transmission coeffi cients of coaxial strip junction connections transformed to the contact areas by sections of electrically long and short printed stripline transmission lines. The performance of the proposed method for monitoring the parameters of printed strip lines is confi rmed by automated modeling, and its effectiveness is confi rmed by a full-scale experiment. The results obtained are useful to development engineers of integrated microwave technology and specialists in the field of monitoring object parameters in non-standard guide systems.