A rigorous dispersive characterization of microstrip cross and T junctions

A full-wave spectral-domain analysis is applied to the characterization of multiport microstrip discontinuities. This method uses the moment method to find the currents in the microstrip circuits and subsequently the scattering parameters of the junctions. In this approach, all the physical effects are considered, including radiation and surface waves. The numerical results for a T- and a cross-junction are presented and agree well with the quasi-static values at low frequencies. The S-parameters of a T-junction are further compared with the measured results, with excellent agreement. The utilization of a shaped T-junction as a broadband equal-power divider is also discussed