Simulazione numerica di circuiti non lineari a commutazione

In questo lavoro si vuole illustrare la struttura e le principali caratteristiche di un programma realizzato per effettuare per l'analisi assistita al calcolatore di circuiti non lineari a commutazione. Il programma determina le equazioni di stato della rete sotto esame e le risolve con la tecnica dell'esponenziale di matrice. Per la formulazione delle equazioni di stato è stata sviluppata un'estensione dell'algoritmo proposto da Chua e Lin per le reti lineari attive. Il programma proposto per la simulazione di circuiti contenenti dispositivi elettronici di potenza allo stato solido, pur ricorrendo ad un modello molto semplice (componenti a semiconduttore come interruttori ideali), consente la massima generalità. Per saggiare le capacità del programma sono stati simulati due semplici convertitori. I risultati sono stati confrontati sia con dati sperimentali, sia con simulazioni eseguite con il programma PSPICE. Il confronto ha mostrato un buon accordo tra simulazione e dati sperimentali nei limiti degli errori di misura. I risultati dell'analisi nel dominio del tempo ottenuti con l'algoritmo sviluppato e con PSPICE hanno mostrato un buon accordo dal punto di vista numerico, mentre dal punto di vista dei tempi il codice di calcolo proposto presenta tempi sensibilmente inferiori.

New Nonlinear Modeling Techniques for Microwave and Millimeter-wave Circuit Design

none3Wireless and mobile telecommunication applications in the lower microwave frequency range have become commonplace. To be able to offer higher data rates to the demanding market, research is gradually focusing towards millimeter wave frequencies. The advantage of millimeter waves is that they are capable of providing wide (in the absolute sense) bandwidth for very high-speed wireless access. Next, millimeter wave networks are becoming viable due to cost reduction in semiconductor devices. This workshop aims at informing the attendees about the recent developments in this area. The workshop includes overview talks on emerging wideband millimeter wave applications. Recent advances in circuit design using various device technologies will be covered in great detail. As these progresses are intrinsically connected with developments in modelling and measurement techniques, those aspects are addressed as well. Ample time will be foreseen to allow interactions between attendees and speakers.noneA. Raffo; A. Santarelli; G. VanniniA. Raffo; A. Santarelli; G. Vannin

A Ku Band Monolithic Power Amplifier for TT&C Applications

The paper describes the design of a 38 dBm monolithic power amplifier at Ku band. The amplifier has to be used as the final stage of the downlink transmitter of a TT&C system. A commercial power p-HEMT process capable of handling a power density higher than 1 W/mm of active area has been selected for the amplifier design. The power capability of this process makes it possible to integrate in a monolithic chip the functionality up today supplied by hybrid modules. Since the circuit is a space product, the attention is focused on reliability issues; therefore performances have to be matched imposing the devices to work at de-rated conditions respect to the process maximum ratings. In this perspective, the device channel temperature becomes a very tight design objective and has to be carefully controlled by means of a thermal simulator. The paper describes the three dimensional thermal model built to predict the devices thermal behavior in the environment of a finite difference thermal simulator. The design of the circuit is also described from the specifications to the final layout

Design of Low Phase Noise Dielectric Resonator Oscillators with GaInP HBT devices exploiting a Non-Linear Noise Model

This paper presents the design, implementation and characterization of two dielectric resonator oscillators (DRO) at 7.61 GHz. The circuits consist of a negative resistance monolithic bipole coupled in a series feedback configuration with a ceramic dielectric resonator. The two circuits exploit different sizes for the active device. The adopted monolithic process is a commercially available GalnP HBT with very good low frequency noise performance. The measured phase noise performance of the two circuits are -120 dBc/Hz and -135 dBc/Hz @ 10 kHz from the carrier respectively, which represent to the authors' knowledge state-of-the-art performance for this technology and resonator type. These excellent results have been obtained by means of a proper large signal design technique and exploiting the predictive capability of a non-linear cyclostationary noise model, which proves its excellent predictive capability for these very low phase noise levels

Non-linear Measurement-Based Noise Models of Electron Devices for Low Phase-Noise Oscillator Design

requirements in terms of oscillator phase noise. Moreover, many applications market requirements drive towards low-cost, integrated voltage-controlled solutions in which high-Q components are not easily supported. Finally, during the last few years a deeper understanding has been achieved on noise mechanisms in oscillators both from a device and a circuit standpoint, and more accurate simulation approaches have been developed and implemented in available CAD tools. This enables device and circuit designers to exploit additional degrees of freedom in innovative oscillator design, provided of course that accurate noise device models are available for the oscillator active elements. This workshop provides a comprehensive overview on recent advances in several areas of low-noise oscillator design, starting from the physical foundations of oscillator noise and physics-based device-level noise simulation. Innovative approaches to circuit-level device modelling for oscillator phase noise analysis are then reviewed, also dealing with the measurement procedures needed for the transistor non-linear noise characterization. Some contributions on selected areas in oscillator design are also presented, by focussing on different possible choices in terms of device technologies and circuit topologies for the implementation of low phase noise, fully integrated VCO circuits. Finally, the relationships between timing jitter, which pays an important role in determining the bit-error-rate of communication systems and possible synchronization problems in clocked, sampled-data systems, and various kinds of spectral characterizations of phase noise generated in oscillators and PLLs will be analyzed and discussed

Nonlinear Dispersive Modeling of Electron Devices Oriented to GaN Power Amplifier Design

This paper presents a new modeling approach accounting for the nonlinear description of low-frequency dispersive effects (due to thermal phenomena and traps) affecting electron devices. The theoretical formulation is quite general and includes as particular cases different models proposed in the literature. A large set of experimental results, oriented to microwave GaN power amplifier design, is provided to give an exhaustive validation under realistic device operation

A New Technique for Thermal Resistance Measurement in Power Electron Devices

A simple technique is proposed for the thermal resistance measurement of electron devices. The new approach is based on the standard measurements which are normally carried out for the electrical characterization of power devices, without requiring special-purpose instrumentation and/or physics-based temperature-dependent electrical device models. Experimental results, which confirm the validity of the new method, are provided