EMI Source Microscopy via Spectral Domain Transformation
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Solution Overview
Problem
Conventional near-field EMI probing methods face challenges such as measurement of evanescent waves that do not contribute to far-field radiation, mutual coupling between the probe and DUT, and spatial inaccuracy in determining radiating field components, making it difficult to accurately locate radiation sources in electromagnetic interference debugging.
Innovation Solution
A system and method using discrete Fourier transform on measured field components at different sampling locations, with a complex phase adjustment to translate these values back to the DUT's surface, allowing for accurate derivation of field component values and identification of radiation sources, similar to 2D synthetic aperture radar techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional near-field EMI probing is used to measure field components, then measurement capability is provided, but measurement precision deteriorates due to spatial inaccuracy in determining radiating field components
Solution Approach 1:
The patent transforms the measurement problem from near-field spatial domain to far-field spectral domain by performing discrete Fourier transform on near-field measurements. This dimensionality change allows accurate determination of radiating field components and their spatial locations by analyzing the spectral content rather than directly measuring in the near-field spatial domain, thereby resolving the spatial accuracy issue.
Solution Approach 2:
The patent introduces an intermediary processing step (discrete Fourier transform and spectral analysis) between the near-field measurement and the radiation source identification. This intermediary transformation process converts the problematic near-field measurements into useful far-field radiation information, acting as a mediator that bridges the measurement capability with the desired measurement precision.
2Reliability
If near-field probing is used to find dominant radiation sources, then radiation source identification is enabled, but measurement reliability deteriorates due to mutual coupling between probe and DUT
Solution Approach 1:
The patent uses spectral analysis as an intermediary that processes the near-field measurements to extract far-field radiation information. This intermediary approach allows the system to identify radiation sources without requiring direct near-field probing that causes mutual coupling, thereby maintaining reliability while avoiding the harmful coupling effect.
Solution Approach 2:
The patent extracts the useful far-field radiation information from the near-field measurements through spectral analysis. By taking out and analyzing the spectral components, the system can identify radiation sources without the physical probe interacting directly with the DUT in a way that causes mutual coupling, thus improving reliability.
3Measurement precision
If near-field measurements are performed to identify radiation sources, then source detection capability is provided, but measurement precision deteriorates due to measurement of evanescent waves that do not contribute to far-field radiation
Solution Approach 1:
The patent performs discrete Fourier transform on the near-field measurements to transition from the spatial domain to the spectral domain. In this transformed domain, evanescent waves (which do not contribute to far-field radiation) can be distinguished from true radiating components based on their spectral characteristics, allowing precise measurement of only the radiating field components.
Solution Approach 2:
The spectral analysis process serves as an intermediary that filters and identifies true radiating components from the near-field measurements. This intermediary step separates the useful radiating information from the contaminating evanescent waves, enabling accurate measurement of only the components that contribute to far-field radiation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the accuracy of radiation source analysis by effectively translating measured field components back to the DUT's surface, overcoming the limitations of conventional methods and enabling precise identification of radiation sources for effective EMI debugging.
Implementation Method 1
The electrical analyzing instrument, which is connected to the measurement probe, is configured to measure field component values at the different sampling locations using the measurement probe
Implementation Method 2
The processing system is configured to perform discrete Fourier transform on at least the measured field component values, to multiply the results of the discrete Fourier transform by a complex phase adjustment term to translate the measured field component values back to locations on the surface of the DUT
Data Source
AI summary
A system and method for performing radiation source analysis on a device under test (DUT) uses discrete Fourier transform on measured field components values at different sampling locations away from the DUT to derive field component values at locations on the DUT. The results of the discrete Fourier transform are multiplied by a complex phase adjustment term as a function of distance from the sampling locations to the DUT to translate the measured field component values back to the locations on the surface of the DUT.