Pratik Maheshwari

Application of Emission Source Microscopy Technique to EMI Source Localization above 5 GHz

This paper presents the utilization of the emission source microscopy (ESM) technique to localize active sources of radiation on a PCB. For complex and large systems with multiple sources, localizing the sources of radiation often proves difficult. Near-field scanning provides limited information about the components contributing to far-field radiation. Two-dimensional synthetic aperture radar, a well-known technique used to diagnose and align phase array antennas, is adapted as emission source microscopy and utilized here for this alternative application. This paper presents the source localization methodology, along with simulation and measurement results. The results show that the proposed method can detect multiple active sources on a complex PCB.

Real time bridge scour monitoring with magneto-inductive field coupling

Scour was responsible for most of the U.S. bridges that collapsed during the past 40 years. The maximum scour depth is the most critical parameter in bridge design and maintenance. Due to scouring and refilling of river-bed deposits, existing technologies face a challenge in measuring the maximum scour depth during a strong flood. In this study, a new methodology is proposed for real time scour monitoring of bridges. Smart Rocks with embedded electronics are deployed around the foundation of a bridge as field agents. With wireless communications, these sensors can send their position change information to a nearby mobile station. This paper is focused on the design, characterization, and performance validation of active sensors. The active sensors use 3-axis accelerometers/ magnetometers with a magneto-inductive communication system. In addition, each sensor includes an ID, a timer, and a battery level indicator. A Smart Rock system enables the monitoring of the most critical scour condition and time by logging and analyzing sliding, rolling, tilting, and heading of the spatially distributed sensors.

EMI mitigation with lossy material at 10 GHz

In this paper, absorber material is utilized to mitigate an EMI problem in real hardware. For a complex and large system, identification of the source location is the first problem which must be solved to achieve electromagnetic interference (EMI) mitigation. Emission Source Microscopy (ESM) provides a powerful tool for locating the sources of radiation in GHz range on a printed circuit board (PCB). Once the source is identified, a suitable volume of the absorber material is placed on the source location to effectively reduce the radiated power at the frequency of interest. Further measurements of the total radiated power in a reverberation chamber are also performed to validate the EMI reduction method with the absorber material.

Software-based analysis of the effects of electrostatic discharge on embedded systems

This paper illustrates the use of software for monitoring and recording the effects of electrostatic discharge (ESD) on the operation of embedded systems, with the goal of facilitating root-cause analysis of resulting failures. Hardware -- based scanning techniques are typically used for analyzing the effect of ESD on systems by identifying physical coupling paths. This paper proposes software techniques that monitor registers and flags associated with peripherals of embedded systems to detect faults associated with the effects of ESD. A lightweight, cost-effective, and non-intrusive software tool has been developed that monitors and records the status of all registers associated with a designated peripheral under test, identifying the fault propagation caused by ESD in the system, and visually presenting the resulting errors. The tool has been used to detect and visually summarize ESD-induced errors on the SD card peripheral of the S3C2440 development board, using local injection and system-level scanning. Root-cause analysis of these faults can potentially assist in identification of coupling paths of electromagnetic interference, as well as determination of areas of the hardware that are more vulnerable to ESD.

Emission Source Microscopy Technique for EMI Source Localization

For large, complex systems with multiple sources at the same frequency, localizing the sources of radiation often proves difficult. This paper presents an emission source microscopy (ESM) technique derived from synthetic aperture radar (SAR) to localize radiating sources on a PCB. Near-field scanning provides limited information about the components contributing to far-field radiation. This paper presents the source localization methodology, supported by simulation and measurement results. After localizing the sources, the far-field contribution and the total radiated power from each individual source can be estimated. The results show that the proposed method can distinguish between multiple radiating sources on a complex PCB.

An Ethernet Cable Discharge Event (CDE) test and measurement system

A Cable Discharge Event (CDE) is an electrostatic discharge between a cable and a connector. CDEs occur on unshielded Ethernet based communication interfaces and inject currents into the pins directly [1-3]. The charging processes are in general understood; however, the discharge processes are complicated due to the number of pins involved and their connections to a system. Based on an understanding of the factors which determine the severity of a CDE, this article describes how to setup a variety of repeatable CDE tests and how to analyze the measurement results.

Emulation of lossy channels using a low loss microstrip trace with added lossy materials

Long traces or cables usually show a smooth rolloff with increasing frequency leading to Inter-Symbol Interference Jitter. The paper proposes a method for emulating such channel link performance by using a short microstrip trace with added lossy material. The paper focuses on the characterization and selection of lossy materials for emulating long channels using a short low loss trace with added lossy material.

Measurement Methodology for Field-Coupled Soft Errors Induced By Electrostatic Discharge

High-speed low-power mobile devices are sensitive to electrostatic discharge (ESD)-induced soft errors, such as unwanted reset, lock up, loss of user interface, disturbed displays, etc. ESD can couple via current and fields into the internal cabling, printed circuit board traces but also directly into the integrated circuits (ICs). Many portable devices shield nearly all traces using top and bottom layer ground planes, and they apply effective filters at cable entry points such that direct field coupling to the IC can dominate the systems ESD sensitivity. However, a little information is available on the robustness of ICs against direct ESD transient field coupling. A methodology for determining this robustness was developed and applied to a set of consumer electronic ICs to create an initial robustness database. Custom-made electric and magnetic field probes are driven by a 400-ps rise time transmission line pulser to evaluate 37 different ICs. The investigation showed that 50% of the ICs were disturbed at approximately 33 kV/m for the electric field injection and 142 A/m for the magnetic field injection at this rise time. This methodology can serve as the basis for further investigations of ICs. The database can be used to estimate the likelihood of field-coupled ESD-induced soft errors in electronic products.

Optical Tracking Based EM-Field Probing System for EMC Near Field Manual Scanning

This paper introduces a method to visualize the frequency dependent electromagnetic field distribution on complex shaped electronic systems. This is achieved by combining magnetic field probing with an optical tracking system for automatically recording the probe position and orientation. Due to the complexity of the shape of the electronic systems of interest, and for utilizing the expertise of the user, the probe will be moved by manually instead of robotically. With the location from the optical tracking system, 3D near field strength map can be obtained at real time during near field manual scanning.

Coupling Path Visualization using a movable scatterer

Suppressing the coupling path between aggressors and victims is always a major issue in EMC design. However, it would be difficult to identify it. In this paper the coupling paths between two monopole antennas were identified using a movable scatterer. By post processing the data, the coupling paths could be visualized as surface plots.