Modern communication systems, for examples high speed pulse code transmission systems via satellite, impose a wide frequency band over which pulse amplitude and phase distortion must be contained within acceptable limits to preserve the integrity of the output information. The system includes many components whose mismatch, e.g. amplifiers with their fixed parasitic elements, contribute to the degradation of wide band response. Broadband equalizers must be properly inserted along the system to compensate for these inevitable mismatches that occur over the band so as to maintain low levels of distortion. This research deals with three difficult and important problems in broadband matching which are especially (though not exclusively) applicable to distributed gain-bandwidth (GBW) theory of linear passive and active 2-ports which arises in such applications as FET amplifiers where loss and internal feedback are included. Heretofore no complete analytic solution of this problem has been presented. The second considers new broadband matching methods which could give a practical approach to matching loads which are badly mismatched and/or have widely fluctuating input impedances as a function of frequency. Microwave antennas, microwave to optical device coupling structures, and microwave FET amplifiers including the parasitic elements due to packaging as well as those of the intrinsic device are typical applications. The third problem concerns gain-bandwidth performance and the design of coupling structures for multi-device distributed amplifiers using realistic models for the active devices.
