Patent ID: 7199680

Claim:
An RF module, comprising: a first waveguide having a ground electrode and a line-shaped conductor portion for propagating electromagnetic waves in a TEM mode; and a second waveguide connected to the first waveguide, for propagating electromagnetic waves in another mode different from the TEM mode, wherein the second waveguide has a region surrounded by at least two ground electrodes stacked in a vertical direction so as to face each other and conductors for bringing the at least two ground electrodes into conduction, wherein electromagnetic waves in said another mode propagate in the region, and a connecting window is provided in one of the at least two ground electrodes, the first waveguide extends in a stacking direction of the at least two ground electrodes of the second waveguide, an end of the first waveguide is short-circuited and conductively connected to the one of the at least two ground electrodes of the second waveguide at a periphery of the connecting window, and magnetic fields of the first and second waveguides are coupled in an H plane of the second waveguide so that the direction of the magnetic field of electromagnetic waves propagated in the first waveguide and the direction of the magnetic field of electromagnetic waves propagated in the second waveguide match with each other.