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Nonlinear Microwave Circuits Design and Modeling using Behavioral Models Based on Volterra Series and X-parameter

Zargar, Hossein | 2016

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 48650 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engineering
  6. Advisor(s): Banai, Ali
  7. Abstract:
  8. Modern microwave and wireless communications systems are too complex today to permit the complete simulation of the nonlinear behavior at the transistor level of description. This problem presents a significant productivity bottleneck for design engineers. At the bridge between the transistor circuit and the multichip module or RF integrated circuit (RFIC) we use “behavioral models” to describe the nonlinear circuit blocks or ICs in the system. The behavioral models are simplified models of the essential nonlinear behavior of the complex sub-circuits; this simplification means that these models will execute more quickly, and use much less memory than if an entire complex subsystem was simulated at the transistor level. In the recent decade,several approaches are pursued to develop the behavioral models and improve their accuracy.To study and development of RF and microwave circuits’ modeling, we focused on two major aspects of behavioral modeling. in the first part of the thesis, we presented several effective approaches to design microwave amplifiers and oscillators using Xparameters. This modeling approach which provides multi-port, multi-harmonics properties, has a quasi-linear formulations. So X-parameters can be useful for analytical circuits design. In this thesis the proposed design approaches are validated with the simulated data in ADS EDA software.On the other hand, in the later part of the thesis, the behavioral models in time domain are in our scope which describe the memory effects and nonlinear behavior of the microwave circuits. Specially, in this study we have presented a double inputdouble output (DIDO) bilateral low-pass equivalent amplifier behavioral model that takes into account input source and output load termination mismatches. The model is intended for the system-level simulation of amplifier chains subjected to wide band modulated signals, since it can predict the device’s input and output scattered waves and their memory effects, in a wide range of voltage standing wave ratios (VSWR).The model is validated comparing the predicted and measured data of a real 15 W GaN based PA circuit attached to different loads. The obtained results show that, in terms of normalized mean square error, this model can provide dB for VSWR in comparison to a much poorer performance of the conventional single input-single output model.In addition, the model extraction methodology, and its associated laboratory test bench are discussed, noting the limitations of conventional setups for behavioral model extraction and validation. Several extraction procedures for DIDO behavioral model according to their required excitation signals are discussed. The performance of the discussed methods are compared based on the datasets extracted from simulation results in ADS
  9. Keywords:
  10. Constitutive Modeling ; Volterra Series ; Nonlinear Circuits ; Nonlinear Circuit Design ; X-Parameters

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