Electric Field Probe De-Embedding Calibration Based on Through and Line Standards

Abstract

The electric field (E-field) probe has been widely used for electromagnetic interference diagnosis in IEC61967-3. But with the increase in detection frequency, the calibration error caused by the error box of the calibrator can not be ignored. The error in the traditional calibration method (TCM) directly affects the measurement results of the E-field probe. In this paper, a de-embedding calibration method (DCM) is applied to two typical E-field probes (Probe A and Probe B). The DCM can compensate for the effect of the error box and improve calibration accuracy. Different from the TCM using microstrip line as a calibrator, the calibrator of the DCM, as a cost, consists of auxiliary Through standard and primary Line standard. Further, two sets of calibrators for the DCM are designed based on microstrip (MS) structure and grounded coplanar waveguide (GCPW) structure, respectively. Compared with the calibrator of the DCM with MS, the calibrator of the DCM with GCPW is easier to achieve high symmetry. The test results show that the DCM with GCPW can improve the accuracy well, and the symmetry of the calibrator is very important for the DCM at high frequencies. Compared with the TCM with MS, the ripples of the DCM with GCPW can be reduced by 83.6 %. Compared with the TCM with GCPW, the ripples of the DCM with GCPW can be reduced by 50 %, and the attenuation is compensated by 1.3 dB at 20 GHz.