Tristan Dubois

Near-Field Electromagnetic Characterization and Perturbation of Logic Circuits

We propose here a nondestructive electromagnetic (EM) near-field test bench for both EM compatibility and susceptibility of circuits. This setup permits both the collection of the near field and injection without contact of a disturbing EM field, all through a probe. Exhaustive characterizations of probes are undertaken via simulations and experiments. According to their design, they are supposedly linked more to the electric or the magnetic field. Simulations of their EM behavior are undergone to fix their optimal geometries, leading to the best measurement performances. It is shown by both the simulations and the S-parameter measurements that their presence does not interfere with the electric behavior of the device under test. Then, logic circuits are characterized from the EM point of view, with the help of this test bench. Circuits are placed on three different printed boards: one double-sided low-frequency board without a ground plane and two single-sided boards with a ground plane and a design that is more or less optimized. EM near-field mappings highlight the strong field areas of the circuits. The need for a ground plane is highlighted. Field patterns on the traces are linked with those observed on microstrip lines. Then, an EM aggression is injected over a supposed sensitive zone of the circuit. Whichever printed board is considered, a parasitic signal superimposes itself on the output signal of the gates. Deepened studies are undergone to exhaustively explain the phenomena observed.

Probe Characterization for Electromagnetic Near-Field Studies

Probes used for contactless electromagnetic field capture or injection are characterized. Depending on the probe structure, they interact preferentially with the electric or magnetic field. The optimal size of the probes for broad-frequency-band measurements is investigated. However, it is shown particularly for the magnetic field probe that considerations about the size and the structures presented in this paper are not sufficient for a good discrimination between electric and magnetic fields. Then, the space resolution of near-field measurements is discussed, with application to the field capture of a microstrip line under operation.

Effect of Low and High Power Continuous Wave Electromagnetic Interference on a Microwave Oscillator System: From VCO to PLL to QPSK Receiver

This paper presents the effects of a continuous wave electromagnetic interference (EMI) on a discrete microwave phase-locked loop (PLL). Susceptibility of the voltage-controlled oscillator (VCO) is first studied as a standalone circuit before being integrated into the PLL. The effects observed on the VCO alone and when it is integrated into the PLL are analyzed as a function of the frequency and power of the interference signal. Most of the effects observed are due to intrinsic nonlinearities of the VCO. Some of them, like intermodulation and injection pulling can be predicted by the small-signal perturbation theory, while others such as a phase unlocking condition generated by strong EMI injection cannot. Finally, the consequence of using such an EMI affected PLL used as a local oscillator in a QPSK receiver, is examined. In all cases, the EMI is injected at the output of the VCO through inductive coupling.

Characterization and model of temperature effect on the conducted immunity of Op. Amp

Abstract This paper deals with the study and the modelling of temperature effects on conducted immunity of electronic circuits. We focus first on experimental measurements using DPI (direct power injection) test bench for the characterization of conducted immunity associated to an air conditioner that allows warming up the circuit locally. It is shown that the increase of temperature seems to decrease the sensibility of the tested circuit. Secondly the behavioural immunity model (ICIM-CI), developed in VHDL-AMS and taking into account temperature effects is presented. The model is finally validated by comparison with measurements.

Optimal Electric Wave Propagation Parameters on a Transmission Line - Schottky Diode System

This paper explores the optimal conditions for wave propagation on a microstrip line loaded by a Schottky diode. Investigations are undertaken by studying the transmitted power versus frequency, power and place of injection of a continuous sine high frequency aggression signal. The aggression is injected in a near- fleld mode. Coupling conditions between the aggression signal in the 500MHz{3GHz frequency band and the system is thus determined.

Subharmonic Oscillations Induced by Continuous Wave Electromagnetic Interference on a Microwave Phase-Locked Loop

This paper presents measurements, simulations, and a theoretical basis to support the observation of spurious peaks on the output spectrum of a microwave phase-locked loop (PLL) exposed to a continuous wave electromagnetic interference (EMI). It is shown that high-power EMI combined to nonlinear characteristics of the PLL may induce subharmonic oscillation phenomena, which provoke the appearance of spurious peaks on the output spectrum. Measurements show that in addition to their dependence on the EMI power and frequency, these spurious peaks depend also on the natural frequency of the PLL and on its stability. Transient circuit simulations of the PLL allowing the prediction of these spurious peaks are presented. Finally, a theoretical explanation based on an analysis of a second-order PLL is given.

Effects of HPEM stress on GaAs low-noise amplifier from circuit to component scale

Abstract This paper presents a study of High Power Electromagnetics (HPEM) stress effects on a GaAs (Gallium Arsenide) low-noise amplifier (LNA). This work aims to evaluate such electrical stress effect from circuit to component scale in relation to more general Intentional electromagnetic interference (IEMI) studies. Conducted susceptibility measurements were made on a specifically designed device under test (DUT). Those experiments yielded interesting results concerning exposition of the DUT to destructive values of interference power, as well as its response to non-destructive but significant powers. The destruction process has been analyzed using time-domain and frequency-domain measurements.

Effects of ageing on the conducted immunity of a voltage reference: Experimental study and modelling approach

Abstract In this paper, we develop a conducted immunity model based on ICIM-CI approach (Integrated Circuit Immunity Model Conducted Immunity) that takes into account the effect of ageing in the immunity characteristics of a bandgap voltage reference. The modelling approach is briefly described. Then the measurement setup and the ageing procedure are detailed. Finally, the model is established and validated thanks to measurements before and after ageing. This model allows to anticipate the long term electromagnetic compliance of the circuit.

How SI/EMC and reliability issues could interact together in embedded electronic systems?

The design process of integrated circuits is based on guidelines by the technological feasibility to achieve minimum structural size. Furthermore quality criteria like reliability and lifetime of the circuit influence the layout. The density of transistors increases and the supplied voltages as well as the noise margins also increase. In this frame the signal integrity as well as the electromagnetic behavior of IC interconnects, the traces in the printed circuit board, the connections of packages, have to be taken into account. Especially in 3-D integration and under harsh environment conditions the electromagnetic field has to be investigated.

Failure mechanism study and immunity modeling of an embedded analog-to-digital converter based on immunity measurements

Abstract In this paper, the failure mechanism of an embedded analog-to-digital converter (ADC) is studied and its immunity modeling with regard to electromagnetic interferences is presented. Failure causes are identified based on off-chip immunity measurements and without specific knowledge of the ADCs design. Disturbances coupling paths inside the ADC have been recognized as well as the conversion error mechanism. Then, immunity of the ADC is modeled using the ICIM-CI (Integrated Circuit Immunity Model for Conducted Immunity) black-box modeling approach. We show the interest of using the direct power injection (DPI) measurement technique for both analyzing and modeling the immunity of complex integrated circuits.