A Fully Micromachined W-Band Coplanar Waveguide to Rectangular Waveguide Transition

A novel fully micromachined coplanar waveguide (CPW) to rectangular waveguide transition is presented in this paper. A metalized probe is adopted to couple the signal from the CPW to the rectangular waveguide through an aperture located at the center of the bottom broad wall of the rectangular waveguide. The transition was optimized using HFSS 10 over the whole W-band. In the proposed transition, the CPW and the rectangular waveguide are patterned and integrated on the same side of the substrate, while the coupling probe is patterned on the substrate instead of being fabricated separately. These changes make the transition more suitable for RF packaged circuits and easily extendable to THz applications. The measured average insertion loss of the back-to-back structure is 2.25 dB and the return loss is better than 11 dB over the whole W-band.