General technique for the integration of MIC/MMIC'S with waveguides

DETAILED DESCRIPTION The invention relates to the incorporation of a microwave integrated circuit (MIC) or a monolithic microwave integrated circuit (MMIC) with a waveguide by attaching the circuit on a dielectric substrate having a predetermined electrical conductor pattern thereon and then locating the substrate within a section of the waveguide.
In a preferred embodiment, an MMIC is either soldered or epoxied directly onto a metallized surface of a ceramic substrate, with the substrate surface parallel to the electric field and approximately centered within the waveguide.
On the metallized surface of the substrate, the structure includes a unilateral finline transition from the waveguide to a slotline and a broadband balun for converting the balanced slotline mode to the unbalanced microstrip or coplanar waveguide (CPW) on the MMIC.
It is an object of the present invention to couple an MMIC to a waveguide while transforming the impedance and mode of propagation between the waveguide and the MMIC so that energy may be transferred efficiently between the structures.
It is another object of the invention to integrate MMIC's with waveguides in a small lightweight package which can be removed easily for adjustment or repairs and which allows reproducible and non-invasive measurement of the MMIC chips.
It is a further object of the invention to provide a device which may be used with rectangular, square or circular waveguides to accommodate dual, or orthogonally polarized electric fields.
It is a yet further object of the invention to provide an MMIC waveguide transition device that is reliable, less expensive and is simple to fabricate, with little or no machining.
The aforementioned and other objects and features of the invention will become more apparent from the following description taken in conjunction with the drawings.