Precision microwave testing of dielectric substrates

A new fixture for magnetodielectric substrate measurement, based on the junction “round waveguides-a radial waveguide” has been designed. For creating a cell design theoretical base, a rigorous solution of the eigen axially-symmetrical H_ops modes of the waveguide junction containing two identical dielectric inserts is obtained. The electrodynamic computation of this structure has been carried out by the rigorous method, based on the representation of the field superposition in the resonance region. This solution analysis approach yields infinite systems of algebraic second-order equations that makes it possible to obtain values of the unknown substrate permittivity from measured resonant frequencies. The general solution for the proposed structure is then evaluated. The principal advantage of this technique is for measuring a large range of substrate permittivities having no thickness limitation