Effect of Inhomogeneous Medium on Fields Above GCPW PCB for Near-Field Scanning Probe Calibration Application


In this paper, a method is proposed to calibrate a probe by placing it into a known field and referencing its output voltage to the known field. A transmission line is a convenient structure for creating such a known field. This paper presents the effect of the inhomogeneous medium on the near-field generated over a grounded coplanar waveguide (GCPW) printed circuit board (PCB) and reports the field pattern over the GCPW. GCPW PCBs are used to determine the probe factor for near-field scanning applications. A near-field scan is performed to visualize the near-field sources over a device under test (DUT). The near-field is measured by using E- and H-field electromagnetic interference probes. The output of these probes is a voltage and using the probe factor, the field present over the DUT can be determined. To calculate the probe factor, the near-field strength needs to be known using the 3-D simulation. GCPW creates a quasi-TEM field. The effect of non-TEM modes is easily underestimated, such that non-TEM fields prevent the user from determining the unwanted field suppression of probes at higher frequencies.


Electrical and Computer Engineering

Research Center/Lab(s)

Electromagnetic Compatibility (EMC) Laboratory

Keywords and Phrases

Atmospheric modeling; Calibration; Dielectrics; E-field probe; grounded coplanar waveguide (GCPW); H-field probe; near-field scanning; Nonhomogeneous media; probe calibration; Probes; Solid modeling; Transmission line measurements

International Standard Serial Number (ISSN)


Document Type

Article - Journal

Document Version


File Type





© 2019 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

18 Feb 2019