Patent ID: 7701310

Claim:
A transmission line transition for transmitting an electromagnetic wave having a wave length of λg comprising: a waveguide tube; a waveguide tube section comprising a plurality of stacked first dielectric substrates, the waveguide tube section having a hole that forms a cavity connected with the waveguide tube and a plurality of first via holes lined to surround the cavity at a distance δ=n×λg/2 from the peripheral wall of the cavity to penetrate the plurality of stacked first dielectric substrates when n is an integer; and a line transition section comprising a plurality of second dielectric substrates having an antenna pattern disposed on a first side of the line transition section facing the waveguide tube and a horizontal transmission line disposed on a second side of the line transition section opposite to the first side, the plurality of second dielectric substrates being disposed to close one end of the waveguide tube section so that the antenna pattern is electromagnetically coupled with the horizontal transmission line; wherein an entire peripheral wall of the cavity does not have a conductive layer due to the plurality of first via holes that penetrate the plurality of first stacked dielectric substrates; one of the second plurality of dielectric substrates has ground patterns formed on opposite surfaces thereof; second via holes are disposed nearer to the cavity than the first via holes to connect the ground patterns formed on the opposite surfaces of the one of the plurality of second dielectric substances; and the line transition section further comprises a plurality of third via holes that surrounds the second via holes at a distance less than λg/4.