Active Matching with Common-Gate MESFET´s

The electrical performance of the common-gate MESFET input stage across multi-octave frequency bands has been analyzed. Based on the device´s common-source parameters, formulas for the circuit´s admittance and noise parameters have been derived that allow one to calculate its gain, reflection coefficients, and noise figure. The influence of the circuit elements on the input stage´s performance, especially on the noise figure, are studied. Finally, the electrical behavior of a two-stage unit consisting of a common-gate input stage followed by a common-source amplifier stage is discussed.