EXPERIMENT-BASED CHARACTERISATION OF THICK CAPACITIVE STUB IN A RECTANGULAR WAVEGUIDE FOR VECTOR AUTOTUNING PURPOSES

Vladimír Bilík - Ján Bezek

   A method is presented which, based on the measurement of the reflection coefficient, yields an accurate and compact model for a thick capacitive tuning stub in a rectangular waveguide. The stub is described by the usual T-type equivalent circuit with two identical series reactances and a shunt susceptance. Their values are obtained as two-dimensional polynomials of frequency and stub extension in the waveguide. Formulas are derived for the coefficients of the polynomials. The procedure is illustrated by a real-life example.

Keywords: impedance matching, three-stub tuner, capacitive post

[full-paper]