A Ka-band transition between a rectangular waveguide and a suspended stripline (SSL) is proposed. It uses a configuration in which the SSL substrate is perpendicular to the waveguide main axis. A patch printed on the SSL substrate is used to match the characteristic impedance of the waveguide. A set of formulas to facilitate the design of the element is presented. A prototype of the transition was fabricated and the experimental results agree well with the simulations. The proposed element can have the input matching below -15 dB in a 13% bandwidth while maintaining the insertion loss below 0.22 dB.