Normal Mode Impedances of a Coupled Pair of Microstrip Transmission Lines

For guidance in the design of integrated microwave circuit components, data are required on the parameters of symmetrical coupled pairs of microstrip transmission lines. The parameters needed to characterize this structure are the characteristic impedances and velocities of propagation of the two normal modes. In addition, for certain purposes such as investigation of spurious coupling, peak power capability, and gyromagnetic interaction (in the case of nonreciprocal substrate material), information is also required on the r-f field configuration.