ANALYSIS AND DESIGN OF MICROSTRIP-TO-WAVE-GUIDE TRANSITIONS

A wide band, low insertion loss transition from shielded microstrip li ne to rectangular waveguide is analyzed by the mode matching method an d the cascading procedure using generalized scattering matrices. The t ransition consists of a discontinuity between a ridge waveguide and th e microstrip line and a ridge waveguide impedance transformer. The mic rostrip eigenmodes, including complex modes, are obtained by mode matc hing method with LSE and LSM mode expansion. The element values of the equivalent circuit for a ridge waveguide step junction is determined from its S-parameters. Computed results of a 17-22 GHz transition agre e well with available experimental results. This rigorous approach pro vides a useful tool for the optimum design of microstrip to air filled waveguide or dielectric filled waveguide transitions.