An Asymmetric Correction Method for the Differential Double-Loop Magnetic Field Probing System

Symmetry is a critical assumption and an application barrier in a two-port near-field probing system before the asymmetric calibration was proposed. Asymmetric calibration can break through this barrier and benefit probe design and application expansion. In this communication, a novel asymmetric correction method has been proposed to compensate for the influence of the asymmetry element, which is inserted into one side of the probing system. Different from the traditional ultrawideband asymmetric calibration method that highly depends on the symmetry of the calibrator, the proposed method can achieve asymmetry correction using the $S$ -parameter of a symmetric two-port probe and the asymmetric element. The efficiency of the asymmetric correction method is proven by three typical asymmetric measurements, inserting a connector, an attenuator, and a cable. The verified measurement frequency range of the proposed asymmetric correction method is up to 20 GHz.

I. Introduction

Magnetic near-field measurement for analyzing integrated circuit electromagnetic interference [1], [2], [3] becomes increasingly important with the technological development of miniaturization and high frequency. The magnetic field probe and its measurement system are used as an essential diagnostic tool that attracts more attention, such as high-performance probe design [4], [5], [6], characterization [7], [8], [9], and application [10], [11], [12].