Detecting and locating electronic devices using their unintended electromagnetic emissions

Electronically-initiated explosives can have unintended electromagnetic emissions which propagate through walls and sealed containers. These emissions, if properly characterized, enable the prompt and accurate detection of explosive threats. The following dissertation develops and evaluates techniques for detecting and locating common electronic initiators. The unintended emissions of radio receivers and microcontrollers are analyzed. These emissions are low-power radio signals that result from the device\u27s normal operation. In the first section, it is demonstrated that arbitrary signals can be injected into a radio receiver\u27s unintended emissions using a relatively weak stimulation signal. This effect is called stimulated emissions. The performance of stimulated emissions is compared to passive detection techniques. The novel technique offers a 5 to 10 dB sensitivity improvement over passive methods for detecting radio receivers. The second section develops a radar-like technique for accurately locating radio receivers. The radar utilizes the stimulated emissions technique with wideband signals. A radar-like system is designed and implemented in hardware. Its accuracy tested in a noisy, multipath-rich, indoor environment. The proposed radar can locate superheterodyne radio receivers with a root mean square position error less than 5 meters when the SNR is 15 dB or above. In the third section, an analytic model is developed for the unintended emissions of microcontrollers. It is demonstrated that these emissions consist of a periodic train of impulses. Measurements of an 8051 microcontroller validate this model. The model is used to evaluate the noise performance of several existing algorithms. Results indicate that the pitch estimation techniques have a 4 dB sensitivity improvement over epoch folding algorithms --Abstract, page iii

Application of Chip-Level EMC in Automotive Product Design

Integrated circuits (ICs) are often the source of the high-frequency noise that drives electromagnetic emissions from electronic products. A case study is presented where emissions from a printed circuit board containing an automotive microcontroller are reduced significantly through analysis of the coupling mechanisms from the chip to the board and attached cables. Noise generated by the IC is explored through measurements in a semi-anechoic chamber and TEM cell, through near-field scans, and through modifications to the printed circuit board. Noise is driven by the IC through both power and I/O connections. Results show that a ferrite in series with I/O power in this application reduced emissions by 10 dB or more at critical frequencies. Possible causes for emissions from the IC and modifications that might reduce these emissions are discussed

Analog-Digital System Modeling for Electromagnetic Susceptibility Prediction

The thesis is focused on the noise susceptibility of communication networks. These analog-mixed signal systems operate in an electrically noisy environment, in presence of multiple equipments connected by means of long wiring. Every module communicates using a transceiver as an interface between the local digital signaling and the data transmission through the network. Hence, the performance of the IC transceiver when affected by disturbances is one of the main factors that guarantees the EM immunity of the whole equipment. The susceptibility to RF and transient disturbances is addressed at component level on a CAN transceiver as a test case, highlighting the IC features critical for noise immunity. A novel procedure is proposed for the IC modeling for mixed-signal immunity simulations of communication networks. The procedure is based on a gray-box approach, modeling IC ports with a physical circuit and the internal links with a behavioural block. The parameters are estimated from time and frequency domain measurements, allowing accurate and efficient reproduction of non-linear device switching behaviours. The effectiveness of the modeling process is verified by applying the proposed technique to a CAN transceiver, involved in a real immunity test on a data communication link. The obtained model is successfully implemented in a commercial solver to predict both the functional signals and the RF noise immunity at component level. The noise immunity at system level is then evaluated on a complete communication network, analyzing the results of several tests on a realistic CAN bus. After developing models for wires and injection probes, a noise immunity test in avionic environment is carried out in a simulation environment, observing good overall accuracy and efficiency

Interference of Periodic and Spread-Spectrum-Modulated Waveforms with Analog and Digital Communications

In this article, the effectiveness and the limitations of spread-spectrum (SS) modulation techniques employed in switching-mode power converters and in digital systems to mitigate interference with communication equipment are analyzed and discussed under the EMC standard perspective and under an information theoretical perspective, with reference to different real-world scenarios. Substantial difference between potential EMI issues in traditional analog radio/TV broadcasting, digital data lines, and digital links featuring advanced channel coding techniques, e.g. in emerging power line communication (PLC) systems, are highlighted. Practical recommendations on the adoption of SS modulations along with a general reflection on the evolution of EMC requirements are finally given

Novel Thermal Management Strategy for Improved Inverter Reliability in Electric Vehicles

Requirements for electric vehicle (EV) propulsion systems—i.e., power density, switching frequency and cost—are becoming more stringent, while high reliability also needs to be ensured to maximize a vehicle’s life-cycle. Thus, the incorporation of a thermal management strategy is convenient, as most power inverter failure mechanisms are related to excessive semiconductor junction temperatures. This paper proposes a novel thermal management strategy which smartly varies the switching frequency to keep the semiconductors’ junction temperatures low enough and consequently extend the EV life-cycle. Thanks to the proposal, the drivetrain can operate safely at maximum attainable performance limits. The proposal is validated through simulation in an advanced digital platform, considering a 75-kW in-wheel Interior Permanent Magnet Synchronous Machine (IPMSM) drive fed by an automotive Silicon Carbide (SiC) power converter.This work has been supported in part by the European Commission through ECSEL Joint Undertaking (JU) under Grant Agreement No. 783174 (HiPERFORM project), by the Government of the Basque Country within the research program ELKARTEK as the projects ELPIVE (KK-2019/0006) and ENSOL 2 (KK-2020/00077), by the Government of the Basque Country within the fund for research groups of the Basque University system IT978-16, by the Government of Spain through the Agencia Estatal de Investigación Project DPI2017-85404-P, and by the Generalitat de Catalunya through the Project 2017 SGR 872

First principle leakage current reduction technique for CMOS devices

Abstract: This paper presents a comprehensive study of leakage reduction techniques applicable to CMOS based devices. In the process, mathematical equations that model the powerperformance trade-offs in CMOS logic circuits are presented. From those equations, suitable techniques for leakage reduction as pertaining to CMOS devices are deduced. Throughout this research it became evident that designing CMOS devices with high-κ dielectrics is a viable method for reducing leakages in cryptographic devices. To support our claim, a 22nm NMOS device was built and simulated in Athena software from Silvaco. The electrical characteristics of the fabricated device were extracted using the Atlas component of the simulator. From this research, it became evident that high-κ dielectric metal gate are capable of providing a reliable resistance to DPA and other form of attacks on cryptographic platforms such as smart card.The fabricated device showed a marked improvement on the I on/I off ratio, where the higher ratio means that the device is suitable for low power applications. Physical models used for simulation included Si3N4 and HfO2 as gate dielectric with TiSix as metal gate. From the simulation result, it was shown that HfO2 was the best dielectric material when TiSix is used as the metal gate

An overview of power electronics in electric vehicles

In response to concerns about energy cost energy dependence and environmental damage a rekindling of interest in electric vehicles (EV's) has been obvious. Based on the California rules on zero emission vehicles in the United States as well as similar tightened air pollution regulation in Europe Asia and much of the rest of the world the market size of EV's will be enormous. Thus the development of power electronics technology for EV's will take an accelerated pace to fulfill the market needs. This paper reviews the current status of multidisciplinary technologies in EV's. Various challenges of power electronics technology for EV propulsion battery charging and power accessories are explored. © 1997 IEEE.published_or_final_versio