Abstract: A transition device for connecting a coaxial cable to an integrated microwave circuit (MIC) composed of planar lines disposed on a substrate, the device being composed of a coaxial connector having a protruding inner conductor, a tuning screw disposed to form a variable capacitor with the protruding conductor of the coaxial connector and arranged to be adjusted to control the electrical parameters of the device, an intermediate dielectric carrier carrying a planar intermediate line connected to the inner conductor of the connector, the intermediate carrier forming a fixed unit with the coaxial connector and being disposed between the connector and the (MIC) substrate, a housing supporting the fixed unit and the substrate, and two metal bands connecting together the planar intermediate line and the planar line of the microwave circuit and the bottom metallization.