Smith chart based analytical design of lumped transistor amplifiers

Abstract

The design of a radio-frequency or a microwave amplifier, for any load and source impedance, using an analytical design method based on the Smith chart equations is presented. Five different cases are considered namely; (i) maximum gain, (ii) minimum noise figure at both the input and output, (iii) minimum noise figure at the input and maximum gain at the output, (iv) minimum noise figure at the input and a certain gain for the whole network, and (v) broadband output network amplifier design. These designs use the scattering parameters of the transistor and the Smith chart equations and are limited to lossless L-sections only. It is observed that the obtained circuit parameters are accurate compared to those obtained manually working with a Smith chart. Also the broadband design is exact and do not follow the trial and error method used by other authors.