Input/output coupling structure for dielectric waveguide having conductive coupling patterns separated by a spacer

Abstract

Disclosed is an input/output coupling structure for coupling a printed circuit board with a dielectric waveguide having a dielectric body and a conductive film covering the dielectric body. The coupling structure comprises a first conductive pattern formed on the bottom surface of the dielectric waveguide to serve as an input/output electrode, in such a manner as to be surrounded directly by an exposed portion of the dielectric body and further by the conductive film formed around the outer periphery of the exposed portion, a spacer having a surface made substantially entirely of a conductive material and a portion for defining a given space, and a second conductive pattern formed on a principal surface of the printed circuit board and electrically connected to the microstrip line. The bottom surface of the dielectric waveguide is joined to the principal surface of the printed circuit board through the spacer, to allow the first and second conductive patterns to be located in opposed relation to one another and define the space therebetween in cooperation with the spacer. The present invention can provide a simplified structure for mounting a dielectric waveguide on a printed circuit-wiring board to couple the dielectric waveguide with a microstrip line of the dielectric waveguide, and achieve a mode conversion mechanism operable in a wide frequency band and less subject to the influence of the possible displacement between the microstrip line and the dielectric waveguide.