A Broadband Transition between Dielectric and Planar Waveguides at Millimeterwave Frequencies

A variety of transitions between rectangular dielectric waveguides and planar waveguides like microstrip or slotline have been designed to combine the advantages of dielectric wave-guides at millimeterwaves with the excellent hybrid integration capabilities of planar circuits. FDTD field simulations have been applied to analyze and optimize the designed transitions with respect to low insertion and return losses as well as minimized mutual coupling between adjacent transitions. Experimental investigations between 60 and 90 GHz proved the promising results of the simulations with insertion losses between 0.5 and 1.5 dB over the full waveguide band (WR-12). The transitions can well be used for the integration of planar circuits into dielectric waveguides or rod antennas and the designed structures are scalable up to frequencies beyond 100 GHz.