Coupling of NRD-guide filled with low permittivity dielectric between waveguides

A new version of NRD-guide coupling structure is proposed in which a low pe rmittivity dielectric is filled between the coupling waveguides. It takes f ull advantage of the common NRD-guide with more flexibility. The choice of different dielectric materials can optimize the required performance. The c orresponding coupling characteristics are analyzed. Some examples are given to show the new coupling characteristics. An important feature is the enha nced coupling between the waveguides and increased attenuation in the trans verse direction, and this implies a size reduction and enhanced EMC capabil ity. Furthermore, the filling of the low dielectric material between the co upling waveguides makes the structure an integrated unit and especially sui table for realization by micro-electromechanical system (MEMS) or by microw ave integrated circuits.