Title :
A novel technique for measuring small signal S-parameters of an RF/microwave transistor, power amplifying stage for use in power amplifier stability analysis
Author :
Collinson, G. ; Jones, M.
Author_Institution :
Texas Instruments Ltd., Bedford, UK
Abstract :
A novel measurement is described which enables the full small-signal S-parameters of an RF/microwave transistor to be measured while it is simultaneously driven and optimally tuned at a higher frequency as an efficient, class B or class C power amplifying stage. This capability allows a classic, small-signal stability analysis of power amplifiers to be performed across frequencies below the power amplified carrier where parametrically pumped, subharmonic oscillations are often a problem. Measured S-parameters of a GaAs HBT (heterojunction bipolar transistor) operating as an efficient, harmonically tuned, class B, power amplifier stage at 870 MHz are presented across the frequency range 50-700 MHz. Analysis of these results shows the presence of negative resistance in the base and collector that is induced by the carrier.<>
Keywords :
S-parameters; heterojunction bipolar transistors; microwave measurement; power amplifiers; solid-state microwave circuits; stability; 50 to 700 MHz; 870 MHz; GaAs; HBT; RF/microwave transistor; class B; class C; negative resistance; power amplifier stability analysis; power amplifying stage; small signal S-parameters; Microwave amplifiers; Microwave measurements; Microwave theory and techniques; Microwave transistors; Power amplifiers; Power measurement; RF signals; Radio frequency; Radiofrequency amplifiers; Scattering parameters;
Conference_Titel :
Microwave Symposium Digest, 1993., IEEE MTT-S International
Conference_Location :
Atlanta, GA, USA
Print_ISBN :
0-7803-1209-0
DOI :
10.1109/MWSYM.1993.277101
