Highly linear broadband amplifiers with lossless feedback Part 1. Theory
É. P. Abranin, Yu. M. Bruck · International Journal of Electronics · 1990
Circuits are studied of matched broadband amplifiers that use lossless transformer feedback. The latter ensures high stability, linearity, constancy of gain and an extremely low noise figure. Actual parameters of transistors and transformers are accounted for. First, two basic circuits are studied in detail: one with transformer feedback and the other with autotransformer feedback. The latter has been shown to ensure higher linearity and a substantially broader bandpass. Subsequently, lossless current amplification was introduced in both circuits. Two circuits with positive and negative feedback are briefly discussed.