Physics-based large-signal sensitivity analysis of microwave circuits using technological parametric sensitivity from multidimensional semiconductor device models

The authors present an efficient approach to evaluate the large-signal (LS) parametric sensitivity of active semiconductor devices under quasi-periodic operation through accurate, multidimensional physics-based models. The proposed technique exploits efficient intermediate mathematical models to perform the link between physics-based analysis and circuit-oriented simulations, and only requires the evaluation of dc and ac small-signal (dc charge) sensitivities under general quasi-static conditions. To illustrate the technique, the authors discuss examples of sensitivity evaluation, statistical analysis, and doping profile optimization of an implanted MESFET to minimize intermodulation which makes use of LS parametric sensitivities under two-tone excitatio

Dynamic, self consistent electro-thermal simulation of power microwave devices including the effect of surface metallizations

We present an efficient simulation technique to account for the thermal spreading effects of surface metallizations in the self-consistent dynamic electro-thermal analysis of power microwave devices. Electro-thermal self-consistency is achieved by solving the coupled nonlinear system made of a temperature dependent device electrical model, and of an approximate description of the device thermal behavior through a thermal impedance matrix. The numerical solution is pursued in the frequency domain by the Harmonic Balance technique. The approach is applied to the thermal stability analysis of power AlGaAs/GaAs HBTs and the results show that metallizations have a significant impact on the occurrence of the device thermal collapse

Effects of Force Level and Hand Dominance on Bilateral Transfer of a Fine Motor Skill

Our research is about bilateral transfer, a concept in motor learning where skills learned by one limb are "transferred", allowing the opposite limb to benefit from what was learned by the first limb. Previous research into bilateral transfer has raised questions about whether specific aspects of motor coordination are or are not transferred. We wanted to see whether learning to control pinch force by the thumb and index finger is transferable, and if it is, whether the learning transfers equally from either hand. We also want to look into the effects of different force levels on the degree of transfer. We designed a task using a program that takes force levels as inputs and has the participant trace shapes on a screen. By having participants perform with one hand, then practice with the other, and finally perform again with the initial hand, we can measure transfer as the difference in performance before and after practice with the other hand.Kinesiology and Health Educatio

Linking X Parameters to Physical Simulations for Design-Oriented Large-Signal Device Variability Modeling

We propose various techniques extending X parameters to include the effect of active microwave device variability by exploiting TCAD simulations. We discuss two possible implementations into Agilent ADS. Both approaches are validated against full microwave amplifier TCAD simulations

Cyclostationary noise modeling of radio frequency devices

We present a review of the current status of research in the modeling and simulation of cyclostationary (nonlinear) noise properties of semiconductor active devices operated in forced large-signal conditions, a typical operating regime for high-frequency applications. We discuss both the case of physics-based device simulations, where numerical burden is the most important issue, and the derivation of compact cyclostationary noise models. In the latter case, both phenomenological amplitude modulation approaches and the derivation of consistent analytical device descriptions are discussed. We show examples of both physics-based simulations of the noise properties of a realistic high-electron mobility transistor resistive mixer and show for the first time the application of a novel, fully analytical cyclostationary noise bipolar transistor model

A generalized drift-diffusion model for rectifying Schottky contact simulation

We present a discussion on the modeling of Schottky barrier rectifying contacts (diodes) within the framework of partial-differential-equation-based physical simulations. We propose a physically consistent generalization of the drift-diffusion model to describe the boundary layer close to the Schottky barrier where thermionic emission leads to a non-Maxwellian carrier distribution, including a novel boundary condition at the contact. The modified drift-diffusion model is validated against Monte Carlo simulations of a GaAs device. The proposed model is in agreement with the Monte Carlo simulations not only in the current value but also in the spatial distributions of microscopic quantities like the electron velocity and concentratio

A proposal for the idea of a flexible-combination polypill in arterial hypertension

Objective: Modern pharmaceutical strategies in arterial hypertension, as well as in other fields, are directed toward two major apparently contrasting objectives: 1) sim- plification of treatment by grouping multiple drugs into single fixed-combination pharmaceutical units (including “polypill”) to improve patient adherence, and 2: personalization of therapy to tailor treatments according to specific individual aspects including pharmacogenomics. The combined fulfillment of these objectives would conceivably entail the unre- alistic development of a very great variety of fixed-combination polypills, each different for drug composition and dosage. An alternative view that could combine the need for both therapy simplification and personalization may be the concept of a flexible-combination polypill. Design and Methods: In order to test this approach, we are devising a preliminary study aimed to assess the feasibility and efficacy of shifting individual patients’ treatment from multiple daily administration (multi-administration) to a single once-a-day administration (mono-administration) of the same drugs. After approval of Ethical Committee, a cross-over randomized study will be carried out for 24 weeks in 52 well controlled non complicated hypertensive outpatients under multiple therapy with at least one hypotensive drug and/or a statin and/or aspirin. Each subject will remain for an 8 weeks period on multi-administration and for another 8 weeks period on mono-administration of the same therapy; the two peri- ods will be separated by 8 weeks to avoid a carry-over effect and their sequence will be randomized