Theoretical and experimental analysis of resonant microwave reflection amplifiers

In this article, the one-port transistor amplifier (OPTA) is studied in detail. This kind of amplifier offers a higher gain, with higher power efficiency at microwave frequencies, than a conventional two-port transmission amplifier. A new theoretical approach to the analysis of the reflection amplifier is applied, resulting in an analytical expression to estimate the transmission gain. An explanation of the principle of operation of this new resonant circuit type transistor amplifier is presented. Results of the gain characteristics are included, comparing the proposed gain expression with experimental results at L-band.