Full wave optimization is implemented to design a wide band transition from shielded stripline to ridge waveguide. A bandpass ridge waveguide filter, with input/output realized through tapped-in stripline is designed. Using rigorous mode matching technique the generalized scattering matrices of all the building blocks are obtained. Design procedure is described and examples are given to demonstrate the features of the tapped-in coupling structure. The tapped-in structure results in a considerable reduction of the filter's total length compared to the use of two transitions.