Line converter for coupling standing waves to a shield area of a three dimensional waveguide

Abstract

A line converter includes ground conductors, a transmission-line conductor and a coupling-line conductor disposed on a dielectric substrate. A dielectric-filled waveguide includes a lower conductor plate, an upper conductor plate, a lower dielectric strip, and an upper dielectric strip, where the dielectric substrate is sandwiched between the lower conductor plate and the lower dielectric strip, and the upper conductor plate and the upper conductor strip, so that a conductor portion S that is part of the ground conductors of the dielectric substrate defines a shield area of the dielectric-filled waveguide. The coupling-line conductor is coupled to a standing wave generated by the shield area, at a position where the electric-field intensity of the standing wave is high. Subsequently, a plane circuit can be arranged so as to be substantially parallel to the direction in which an electromagnetic wave propagates through the three-dimensional waveguide. Further, the dielectric substrate can be easily machined and the characteristic of coupling between the plane circuit and the three-dimensional waveguide provided on the dielectric substrate is prevented from being affected by the precision of assembling the plane circuit and the three-dimensional waveguide so that a line-conversion characteristic according to a predetermined design can be easily obtained.