• Broadband automated phase measurement
• Uses two probes: a reference probe and a measurement probe
• FFT transformation using an oscilloscope or VNA

Near-field scanning has long been used to identify strong local magnetic sources and is commonly employed to pinpoint causes of unwanted emissions, antenna structures, and coupling paths.

The strength of a local magnetic or electric field does not always indicate which sources couple efficiently to a well-designed antenna or form a good antenna structure. Such issues often rely on the experience of EMC engineers. For example, a weak 125 MHz signal appearing in an unexpected location may be a precursor to a design flaw, even when a strong 125 MHz signal is present on the clock.

Similarly, a very localized and strong emission source may have less effect in the far field than a weak, distributed noise source such as a heatsink. To accurately identify the cause of EMC problems and to obtain models suitable for numerical simulation or module/IC verification, a powerful scanning technique is required.

According to Maxwell’s equations, by determining the magnitude and phase of the near magnetic field around a noise source, it is possible to reconstruct a model of the source to reproduce its radiation or simulate its far-field emissions. The key requirement in this process is information about the phase of the magnetic field, defined as the phase difference between a reference point and all other field points.

Phase can be measured in various ways, but the uniqueness of API’s phase measurement technology lies in its broadband and fully automated approach.

• SmartScan-PM software
• Oscilloscope or VNA (meeting the requirements for each frequency range)
• EMI probes
• Any hardware required for system calibration or signal generation (e.g., comb generator)

Please also see our Rohde & Schwarz products

• EMI Scan
• Phase Measurement
• Near-field to Far-field Conversion
• ESM Noise Emission Microscopy
• Resonance Scan