This study is dedicated to the development of a new design of the shielded low-loss metal-dielectric waveguide for the frequency range of 90–100 GHz. High level of losses in metal is a major challenge complicating implementation of commonly used waveguides in the specified wavelength range. The study objective was to develop the proposal regarding the waveguide design with losses lower than 0.5 dB/m, with persistent wave polarisation. To address the problem, we analysed various waveguide design solutions and estimated losses per unit length along with the possibility to implement the proposed design. We proposed the final variant of waveguide design and selected parameters of structural members to solve the problem at hand.