Input/output coupling structure of dielectric waveguide
Dielectric waveguide comprising dielectric body having an exterior coated with an electrically conductive film. Region in one side surface couples to another dielectric waveguide, and slot in bottom surface exposes the dielectric body in an L-shape in two adjacent side surfaces, except for the one side surface. Front surface of printed circuit board has a ground pattern opposed to the slot, which includes opening with outer shape greater than slot, and a back surface having a ground pattern surrounding a strip line disposed to cross through the slot. A distal end of the strip line and the front surface-side ground pattern are coupled together by a via hole. The opening is surrounded by a via hole group which couples the front and the back surface-side ground patterns together. The dielectric waveguide is disposed to allow the opening and the slot to be opposed to each other.
1. A dielectric waveguide input/output coupling structure for coupling an electrode of a dielectric waveguide and a strip line on a printed circuit board together, the dielectric waveguide being configured to be coupled to other dielectric waveguide, wherein:
the dielectric waveguide comprises an approximately rectangular parallelepiped-shaped dielectric body having an exterior coated with an electrically conductive film, and has one side surface having a coupling region for coupling to other dielectric waveguide, and a bottom surface having a slot for exposing the dielectric body in an L-shape, the L-shape being formed by two linear slots crossing with each other at their end portions, each of the linear slots being parallel to respective one of two adjacent side surfaces, except for the one side surface, of the dielectric waveguide;
the printed circuit board has a front surface having a front surface-side ground pattern provided at a position opposed to the slot, which includes an opening having an outer shape greater than that of the slot, and a back surface having a back surface-side ground pattern and a strip line surrounded by the back surface-side ground pattern and disposed to cross through the slot, and
wherein a distal end of the strip line and the front surface-side ground pattern are coupled together by a via hole, the opening is surrounded by a via hole group which couples the front surface-side ground pattern and the back surface-side ground pattern together, and the dielectric waveguide is disposed in such a manner as to allow the opening and the slot to be opposed to each other.
2. The dielectric waveguide input/output coupling structure as defined in claim 1 , wherein the strip line and the slot cross with each other at a position having approximately equal distances along the opening from each of opposite ends of the slot.
3. The dielectric waveguide input/output coupling structure as defined in claim 2 , wherein the via hole is located near the slot.
4. The dielectric waveguide input/output coupling structure as defined in claim 2 , wherein the via hole group surrounds the opening in a triangular shape formed by chamfering one corner of a quadrangular shape.