HIGH POWER MILLIMETER WAVE RADIAL COMBINER FOR SOLID-STATE APPLICATIONS

AN EFFICIENT WAY TO COMBINE OUTPUTS FROM MULTIPLE SOLID-STATE AMPLIFIERS USES A CAVITY STRUCTURE. THEIR ADVANTAGES INCLUDE: LOW LOSS, AMPLITUDE AND PHASE BALANCE, LARGE NUMBER OF INPUT PORTS, BROAD BANDWIDTH AND HIGH POWER HANDLING. THEIR MAJOR DISADVANTAGE, HOWEVER,IS THAT THEY MODE. MODING, WHICH CAUSES ISOLATION PROBLEMS, WILL OCCUR WHEN THE AMPLIFIERS ARE DISSIMILAR OR WHEN FAILURES EXIST UNLESSTHE COMBINING STRUCTURE IS PROPERLY DESIGNED. PREVIOUS DESIGNS HAVE AVOIDED MODING BY USING MODE OBSORBERS AND/OR EXTERNAL ISOLATORS, WHICH INCREASES INSERTION LOSS. IN ORDER TO PROPERLY DESIGN SUCH A STRUCTURE, ONE MUST BE ABLE TO THEORETICALLY PREDICT A COMPLETE SCATTERING MATRIX NETWORK DESCRIPTION, NOT MERELY THE IMPEDANCE TRANSFORMATION PROPERTIES. THIS DIFFICULT MATHEMATICAL PROBLEM, HERETOFORE UNSOLVED, HAS RECENTLY BEEN SOLVED BY THE STAFF OF FLAM & RUSSELL, INC. (FR). USING THIS S-MATRIX COMPUTER MODEL IN CONJUNCTION WITH MODELS FOR MILLIMETER-WAVE SOLID-STATE AMPLIFIERS WILL OPTIMIZE THE DESIGN OF THE MILLIMETER-WAVE COMBINER. FR RECENTLY APPLIED THIS APPROACH TO A 60-WAY COMBINER FOR AN S-BAND RADAR TRANSMITTER, AND A 24-WAY DIVIDER FOR A KU-BAND ANTENNA ARRAY.