Abstract—Explorations and experimentations of Volttera-series-based behavior models are presented in this report. Basic model structures including a frequency shaping block and a resistive nonlinear gain block are analyzed algebraically and experimentally. A compositional model based on the two basic models is presented, and its measuring strategy is also discussed. Predicted performance matrices (harmonic and inter-modulation distortions) based on the experimental models are compared to the Spectre simulations results using time-consuming periodic steady state analysis. Our analysis on the accuracy of the models show that GX model gives relatively more accurate results on harmonic distortions than YG, and YG model gives relatively more accurate results of inter-modulation distortions than GX. GXG, the compositional model, gives very accurate estimation of inter-modulation at small input signal levels. I. INTRODUCTION AND PROJECT GOAL he quality of analog top-down design methodologies is heavily influenced by the quality of models available at high T level of abstraction. At the system level, efficient behavioral model are required in order to evaluate performances and interactions with the digital side. When considering RF circuits, non-linear effects become more involved and have to be accounted for using the Volterra theory of non-linear systems. From a practical point of view, direct

Abstract- In this paper we propose a frequency-separation methodology to generate system-level macromodels for analog and RF circuits. The proposed macromodels are similar in form to those based on Volterra kernel calculations, but are much simpler in terms of characterization and overall model complexity, and can be derived from existing device models. This simplicity is realized by applying some basic assumptions on the form of the input excitations, and via separation of the nonlinearities from the dynamic behavior. In addition, by further separating the ideal model functionality, this macromodel is applicable to strongly nonlinear components such as mixers. While time-varying Volterra series models have been proposed for mixers with a fixed local oscillation (LO) signal, the proposed frequency separation model is completely general and can capture the variations of the LO input during a system-level simulation. The proposed macromodels are demonstrated in a system-level simulation tool based on Simulink for efficient evaluation of the entire RF system and associated components. A GSM receiver system in 0.25pm CMOS process is used to demonstrate the efficacy of these macromodels in our system-level simulation environment. I.

iii iv ACKNOWLEDGMENTS Although learning scientific facts and contributing to it has always been the main motivation during my last two years, living a scientific life with an elite group of people in an excellent place is the best experience which I did not have much of it before I came to Sabanci University. The work described in this thesis could not have been accomplished without the help and support of others. Here, I hope that I can express at least some part of my appreciation to all those who have helped my professional as well as personal life in the past few years. First of all, I want to thank my thesis advisor, Assoc. Prof. Yasar Gurbuz. What I learned from him goes well beyond pure academics. I would like to acknowledge his personal assistance during my admission to Sabanci University and for helping me in adapting to the new environment. I would also like to thank him for giving me the opportunity to do the research I liked to do, and lastly for his major support for my future career. I look

An efficient distortion analysis methodology is presented for analog and RF circuits that utilizes linear-centric circuit models to generate individual distortion contributions due to each nonlinear component in a circuit. The per-nonlinearity distortion results are obtained via a straightforward postsimulation step that is simpler and more efficient than the Volterra series-based approaches and does not require high-order devicemodel derivatives. For this reason, the order of analysis can be significantly higher than that for a Volterra series-based implementation while fully accounting for all distortion effects using most existing device models. Moreover, the proposed methodology can also analyze per-nonlinearity distortion for active switching mixers and switch capacitor circuits when they are modeled as periodically time-varying weakly nonlinear systems. The proposed methodology provides important design insights regarding the relationships between design parameters and circuit linearity, hence, the overall system performance. Circuit examples are used to demonstrate the efficacy of the proposed approach, and interesting insights are observed for RF switching mixers in particular.