Abstract: A waveguide able to operate at frequencies above 20 GHz is embedded in a printed wiring board. The waveguide is formed by evacuating a waveguide path through one or more dielectric layers of the board and joining the layers. After the layers are joined, the waveguide cavity is electroless copper plated by providing an electroless plating solution in the cavity. Thereafter, the cavity walls are electroplated to form seamless electrically conductive walls for the waveguide. A dielectric may also be provided in the cavity if desired. Electronic components may be formed in the waveguide by evacuating one or more layers of a printed wiring board in a similar manner, interconnected to the waveguide. In one embodiment, the components may convert the frequency of the signal carried in the waveguide so that higher frequency signals are processed within the RFI EMI protection of the layers of the wiring board.