This invention relates to microwave power combiners using solid state amplifier devices and to planar transitions from waveguide to microstrip or vice versa.
Combining the power from several FET amplifiers is a current approach for obtaining higher power microwave solid state power sources. The combining efficiency must be increased and the fabrication costs must be reduced to make this approach competitive with conventional vacuum tube power sources such as traveling-wave tubes. The successful solution will simultaneously satisfy all the important requirements of low cost, high combining efficiency and broad bandwidth, and does not use coaxial connectors.
A fin-line transition from waveguide to microstrip is inherently low loss. A single transition in a single waveguide is described in J. H. C. van Heuven, IEEE Transactions on Microwave Theory and Techniques, Vol. MTT-24, No. 3, March 1976, pp. 144-147.