Anna Gina Perri

A Semiempirical SPICE Model for n-Type Conventional CNTFETs

We present a compact, semiempirical model of carbon nanotube field effect transistor easily implementable in simulation SPICE software to design analog and digital circuits. The model is based on analytical approximations and parameters extracted from quantum mechanical simulations, having compared the results with those of the numerical model online available and of experimental data.

Very fast and accurate modeling of multilayer waveguiding photonic bandgap structures

A model of one-dimensional (1-D) waveguiding photonic bandgap (PBG) structures, based on leaky mode propagation (LMP) method, is proposed for the first time. A complete analysis of the propagation characteristics, including the determination of modal propagation constants, electromagnetic field harmonics and total field distribution, transmission and reflection coefficients, total forward and backward power flow in the structure, guided and radiated power, and total losses, has been carried out for a finite extension configuration. The numerical results have been compared with those obtained by using other methods, showing a very good agreement together with some significant advantages in terms of very low computational time, absence of any a priori theoretical assumptions and approximations, capability of simulating the actual behavior of the device as a reflector, and fast determination of the bandgap position.

A New System for Continuous Monitoring of Breathing and Kinetic Activity

We present a new system for acquiring simultaneously breathing rate and kinetic activity over a period of twenty-four hours. The system is based on a couple of sensors, which are very light, absolutely noninvasive, and compatible with everyday life. The proposed breathing sensor is cheap and uses a conductive rubber as active material. An analog signal representing the breathing rate is obtained from the sensors signal, breath by breath, without any averaging or filtering. The kinetic activity sensor is based on a tiny accelerometer whose signal is averaged and filtered, so that both sensors have voltage compatible with a slow data logging.

Modeling of fully etched waveguiding photonic bandgap structures

Modeling of a 1-D finite-height, finite-length fully etched waveguiding photonic bandgap structures, based on the leaky mode propagation method, is proposed for the first time. So far only infinitely long gratings have been modeled by this approach. Finite extension structures having deep grooves, high refractive index contrast, and an arbitrary profile of the etched region can be modeled in very short computer time, starting from the infinitely-long photonic bandgap structure. Useful analytical and closed-form expressions for the reflection and transmission coefficients and out-of-plane losses are derived, which are valid for any operating conditions. One of the most important applications of the model relevant to 1-D photonic bandgap devices is to determine the losses occurring also in 2-D devices. Comparisons of results in terms of transmittance, losses, bandgap position and complex propagation constant with those obtained by the bi-directional mode expansion and propagation method and an exact vectorial method show an excellent agreement together with a strongly reduced CPU time for our method. Full investigations of three different etching profiles (i.e., rectangular, triangular and saw-tooth) are carried out. Particular attention is paid to the physical behavior around the first and second Bragg interaction regions. We demonstrate that the rectangular shape exhibits the highest losses and the widest bandgap, while the saw-tooth grating exhibits the lowest losses and the narrowest bandgap. Quick and accurate determination of the out-of-plane losses in a large variety of photonic bandgap devices is also demonstrated.

A new pressure sensor-based electronic medical device for the analysis of lung sounds

In this paper a new pressure sensor-based electronic device for the analysis of lung sounds has been designed and prototyped. The device allows the effective auscultation, the accurate processing and the detailed visualization (temporal and frequency graphs) of any lung sound. Moreover it is suitable for the continuous real-time monitoring of breathing functions, resulting very useful to diagnose respiratory pathologies. It provides medical specialists with a totally non-invasive high-engineering device able to detect and analyze the widest number of data for the monitoring of the respiratory system by the simple recording and evaluation of lung sounds being a substantiated correlation between lung sounds and diseases.

High Quality Heart and Lung Auscultation System for Diagnostic Use on Remote Patients in Real Time

We propose a medical electronic-computerized platform for diagnostic use, which allows doctors to carry out a complete cardio-respiratory control on remote patients in real time. In the context of telemedicine the proposed system can be considered as a really innovative product in which all the most advanced technologies of biomedical engineering converge to guarantee an efficient and reliable home assistance that allows the patient a highly better quality of life in terms of prophylaxis, treatment and reduction of discomfort connected to periodic patient controls and/or hospitalization. Moreover the system has been equipped to be employed also to real-time rescue in case of emergency without the necessity for data to be constantly monitored by a medical centre. In fact, when an emergency sign is detected through the real-time diagnosing system, it sends a warning message to people able to arrange for his/her rescue. A Global Positioning System (GPS) also provides the patient coordinates. The proposed system, in its version for diagnostic use, has been verified by the heart specialists of the Institute of Cardiology in the General Hospital (Polyclinic) of the University of Bari, Italy.

Biomedical Electronic Systems to Improve the Healthcare Quality and Efficiency

The most recent developments of electronics, informatics and telecommunications let imagine applications in the biomedical engineering field to improve the healthcare quality (She et al., 2007). In particular a number of systems has been developed in the telemedicine and home care sectors which could guarantee an efficient and reliable home assistance allowing a highly better quality of life in terms of prophylaxis, treatment and reduction of discomfort connected to periodic out–patient controls and/or hospitalization for the patients afflicted by pathologies (such as cardiac decompensation or obstructive chronic bronchopathy), and allowing considerable savings on sanitary expenses. In this chapter we present a review of our principal projects in biomedical electronic field, developed at the Electronic Device Laboratory of Polytechnic of Bari, Italy. Firstly we propose a medical electronic-computerized platform for diagnostic use, which allows the doctor to carry out a complete cardio-respiratory control on remote patients in real time. The system has been patented and has been designed to be employed also to realtime rescue in case of emergency without the necessity for data to be constantly monitored by a medical centre, leaving patients free to move. For this purpose the system has been equipped with highly developed firmware which enables automated functioning and complex decision-making. In fact, when an emergency sign is detected through the real-time diagnosing system, it sends a warning message to people able to arrange for his/her rescue. A Global Positioning System (GPS) also provides the patient coordinates. All this occurs automatically without any intervention by the user. The system might be useful also to sportsmen. Thanks to its characteristics it can help to reduce hospitalization rates and length of stays thereby improving health costs and quality of life. Moreover the system, in its version for diagnostic use, has been verified by the heart specialists of the Institute of Cardiology in the General Hospital (Polyclinic) of the University of Bari. We also propose a low-cost, electronic medical device, designed for the non-invasive continuous real-time monitoring of breathing functions. It diagnoses respiratory pathologies by the electronic three dimensional (3-D) auscultation of lung sounds, performing a correlation between lung sounds and diseases. Moreover we present a new system for acquiring simultaneously some health parameters which are strongly correlated: breathing rate and kinetic activity. The system is based on a

Multiple defect characterization in finite-size waveguiding photonic bandgap structures

A powerful and efficient model recently proposed by the authors based on the leaky mode propagation method is used to characterize photonic bandgap structures incorporating multiple defects, having arbitrary shape and geometrical parameter values. The importance of the defect-mode characterization in photonic bandgap materials is due to the intensive use of defects for light localization to design very promising optical devices. This paper provides a new, efficient method to model defects in waveguiding, finite-size photonic bandgap devices and analytical and closed-form expressions for the reflection and transmission coefficients and out-of-plane losses,which is very useful and easily implemented under any operating conditions. Moreover, the method has been applied to examine the capabilities of waveguiding photonic bandgap devices in dense wavelength division multiplexing filtering applications. Therefore, the design of two optical filters for such applications has been carried out and optimal design rules have been drawn using the new model.

Thermal and electrical layout optimisation of multilayer structure solid-state devices based on the 2-D Fourier series

In this paper a 2-D Fourier transform-based analytical method for the thermal and electrical layout optimisation of multilayer structure solid-state devices is proposed. Compared with previous models presented in literature, it is general and can be easily applied to a large variety of integrated devices, provided that their structure can be represented as an arbitrary number of superimposed layers with a 2-D embedded thermal source, so as to include the effect of the package. The proposed method is independent of the specific physical properties of the layers, hence GaAs MESFETs and HEMTs as well as Silicon and Silicon-On-Insulator MOSFETs and heterostructure LASERs can be analysed. Moreover, it takes into account the dependence of the thermal conductivity of all the layers on the temperature; the heat equation is solved coupled with the device current-voltage relation in order to give physical consistence to the experimental evidence that a temperature increase causes a degradation of the electrical performances and that the electrical power is not uniformly distributed.

DC thermal modelling of GaAs MESFETs based on a semiempirical approach

In this paper a new semiempirical large signal thermal model of GaAs MESFETs is proposed for DC characterization. The model includes a third order dependence of fitting parameters on bias conditions and three thermal fitting parameters. A number of GaAs MESFETs, each very different from a geometrical and technological point of view, have been characterized as a function of temperature and modelled with high accuracy. The CPU extraction time results are moderate in any example. Results have been compared with the Rodriguez–Tellez model, showing improvements in accuracy of better than 30%. The model can be successfully used in MMIC CAD applications.