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Spatial Blind Spot Reduction
For EMxpert EHX Models
The Interleaved Scan is meant to overcome the limitations of the probe polarizations. Each of the 1218
probes on the EMxpert EHX scanner is created by using the vias and traces in a PCB to form a loop. This
small loop does not respond well to magnetic fields parallel to it, essentially creating a blind spot.
The response of a single probe to magnetic fields in a given orientation is shown below.
It was chosen to orient this blind spot at 45° and further to rotate every other row by 90° so that consecutive
rows do not have the same blind spots. Because of this arrangement the blind spot can be eliminated by
measuring a DUT twice with a small physical shift between scans.
For EMxpert EMX Model
Each of the 1218 probes on the EMxpert EMX scanner is created from two overlapping loops to increase
their angular coverage. Even with this hybrid approach they do not have 360 degree coverage. There is
one orientation of magnetic field that the probes do not respond to, essentially creating a blind spot. This
blind spot can be eliminated by measuring a DUT twice with a small physical shift between two scans.
A scale model of the probes is shown below. It effectively combines two separate loop probes into one
“X Loop”.
EMxpert Software
Spatial Blind Spot Reduction
