Pierre Savary

A unified approach for the linear and nonlinear stability analysis of microwave circuits using commercially available tools

For the first time, an exhaustive linear and nonlinear stability analysis of multi-transistor MMIC circuits is presented. A key point of the proposed stability analysis lies in that it can be easily implemented on any CAD package. Our straightforward and powerful approach allows both linear and nonlinear stability analysis of any complex circuit submitted or not to large RF signals. Following our novel approach, a MMIC HBT power amplifier was analyzed. Division frequency phenomena and spurious oscillations were detected by simulations and confirmed by measurements.

A 60-GHz HEMT-MMIC analog frequency divider by two

This paper describes an analog frequency divider by two working in the millimeter wave frequency range around 60 GHz. This circuit is analyzed with a new method that allows one to determine the steady-state regime of any synchronized circuits with standard CAD commercial software. The method proposed relies upon the concept of open loop systems and is applicable to any feedback transistor circuits. The designed circuit was processed using a standard 0.25-/spl mu/m HEMT technology. Four transistors were used for realizing the frequency division function as well as the input and output amplification. More than 10% frequency lock-in bandwidth was achieved, and conversion gain was obtained using input and output buffers. Measured results were found to be in good agreement with simulated ones. >

Oscillateurs à TEC accordables par varactor dans la bande 18–40 GHz

RésuméUn oscillateur à génération directe couvrant la bande 18–26 GHz ainsi qu’un oscillateur doubleur couvrant la bande 26–40 GHz sont présentés. Ceux-ci utilisent des transistors a effet de champ et des varactors GaAs hyperabrupts. L’intérét de telles réalisations est d’une part la forte intégration et l’ agilité en fréquence de ces sources et d’autre part, dufait de la fréquence élevée, la possibilité de générer une nouvelle gamme d’ oscillateurs accordables sur de trés larges bandes relatives par transposition de frequence.AbstractThis paper describes the design, analysis and experimental results of 18–26 GHz fundamental and 26–40 GHz doubler voltage controlled oscillator. They use field effect transistors and hyperabrupt GaAs varactor diodes. The interest of such circuits are a good integration, a high speed frequency tuning capability and a high frequency of oscillation allowing to achieve ultra wide bandVco by frequency transposition at lower frequencies.