Simple design of broadband monomode tapers between hollow and dielectric filled rectangular waveguides

Broadband tapers which are intermediate between standard and integrated waveguide technology (INWATE) devices, i.e., totally dielectric-filled waveguides, are needed for the measurement of mm-wave circuits constructed according to INWATE principles. The performance of such tapers is calculated perturbationally, yielding simple analytical formulae for the reflection coefficient. Design principles for the minimization of taper length at minimum taper return loss are given, along with a comparison of experimental measurements and theoretical results showing satisfactory agreement.