Contactless microstrip to waveguide transition

A radio or radar transceiver comprising a microstrip to waveguide transition comprising:

• a waveguide module;
• and
• a printed circuit board (PCB),
• wherein the module is arranged to interface with the PCB, the PCB comprising a patch antenna and a ground plane, the module comprising a waveguide aperture and a repetitive structure, the waveguide aperture arranged extending through the module for attaching a waveguide to an external side of the waveguide module, the repetitive structure comprising a plurality of protruding metal or metallized elements arranged to surround the waveguide aperture on an internal side of the module and to define a passage into the waveguide aperture on the internal side,
• wherein the repetitive structure is configured to attenuate electromagnetic signal propagation in a frequency band past the repetitive structure while allowing propagation via the passage, and
• wherein the repetitive structure and ground plane constitute a gap waveguide structure, and
• wherein the repetitive structure is arranged at a distance from the ground plane, where the distance is smaller than a quarter of an operation wavelength of the waveguide module.