Abstract: A new approach,conformal transformation combined with the boundary element method(BEM),is presented for computation of the characteristic impedance of coupled offset cylindrical bars transmission line between parallel plates.By this new method,the numerical results are obtained from three fundamental offset structures.These impedance data not only permit the exact design of various offset configurations of slab lines,but also provide a known accuracy for manufacturing various coaxial configurations of slab lines.

Key words: hybrid method, coupled offset cylindrical bars transmission line between parallel plates, characteristic impedance