A conformal mapping method(CMM)based on curve coordinates is proposed to focus on the problem that the electromagnetic field of the two-dimensional uniform microwave transmission lines with complex geometric boundary conditions is hard to be analytically solved and thus its design is difficult. The method is based on a TEM model of the cross-dimensional electromagnetic transmission line. First
the conformal mapping is used to map the complex boundary curve of the transmission line into boundary curves of a simple transmission line
and the curvilinear coordinates of the complex border transmission lines are built; Then the curvilinear coordinates are used to convert the Maxwell's equations for the complex border transmission lines to the simple border transmission lines
and the electromagnetic mapping between the two kinds of transmission line is formed. Finally
it is verified that both the charge and the potential between two kinds of transmission lines are correspondingly equal
so that the capacitance of complex transmission line that is closely related to the transfer characteristic is obtained and can further be used to guide the design of the transmission line. Simulation results and comparisons with the traditional conformal mapping calculation method with the potential being the intermediate amount show that the CMM method starts directly from the field
eliminates the potential on the intermediate calculations
and its results agree well with theoretical calculation.
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references
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