MICROWAVE integrated circuit of planar type, comprising at least one mesa component, and process for its manufacturing

This invention relates to microwave integrated circuits having planar components and mesa and microstrip lines. In order to maintain a constant impedance to the microstrip lines 12 + 13, comprising the mesa 5 is "buried" in a box 16, then filled with a dielectric 10 having substantially the same coefficient of thermal expansion and the same dielectric constant as the substrate 2 semi-insulating. The surface of the mesa component 5 and the dielectric 10 is in the plane 3 of the planar part of the integrated circuit. Between the microstrip lines 12 interconnecting the planar side 3, and the ground plane 13 on one face of the substrate, the thickness and dielectric constant of the material is constant. Application to microwave circuits .