Bandwidth Limitations and Synthesis Procedures for Negative Resistance and Variable Reactance Amplifiers

Abstract

The bandwidth limitation on the reflection coefficient of circuits containing a reactance limited negative conductance such as a tunnel diode is derived, and the insertion loss method of modern network theory is adapted to the synthesis of low pass ladder equivalents of amplifiers containing these elements. Amplifiers which have a considerable bandwidth advantage over simple single tuned circuits, and which approach the ultimate bandwidth limit as rapidly as possible as the number of passive components is increased, are demonstrated. Fundamental bandwidth limitations of three-frequency nonlinear reactance amplifiers, parametric amplifiers, and non-inverting upconverters are also found. A low pass ladder equivalent circuit and the insertion loss method are shown to be useful tools for synthesis of these amplifiers. Considerable bandwidth advantage over single-tuned circuits is again demonstrated. Syntheses which yield the ultimate bandwidth as the number of circuit elements is increased are found. These synthesis methods and the reverse predistortion technique are used to synthesize stable amplifiers whose bandwidth capability increases almost linearly with the number of active elements employed. Relationships between physically achievable amplifier circuits and the low pass equivalents are shown, and the general compatibility of presently available active elements with these circuits is considered.

Files

Additional details