Analysis of electromagnetic interference under different types of near‐field environments

Abstract

The effect of different interferences on a victim wireless device in electric and magnetic near-field (NF) environments is investigated. Using a four-port transverse electromagnetic (TEM) cell, those NF environments are generated by varying wave impedance in the cell, which can be done by applying an external interference signal. As a measure of interference, the bit error rate performance of the victim device is chosen, which shows both NF environments have significant but distinctive interference effects on the victim device.Introduction: Transverse electromagnetic (TEM) waveguides have been widely used as an alternative approach to perform an electromagnetic compatibility (EMC) test in a far-field environment [1, 2]. However, many EMC issues are not confined to only far-field problems. In practice, many electronic devices coexist in a relatively small area belonging to a near-field (NF) region, which should also be carefully considered in modern EMC tests [3]. To configure a NF-like environment, several methods of manipulating wave impedance inside TEM waveguides have been reported [4][5][6]. However, to our knowledge, no practical interference problems have been dealt with.In this Letter, we quantify interference effects in two different electric and magnetic NF test environments. To do this we also provide a new way of generating the NF environments using a TEM cell. Through the experiment, we can show that the different NF environments have remarkable but distinctive effects on a victim device.

Method to reduce an unwanted EM field component in a 4‐port TEM cell

“…If the same input signals used for the TEM mode applied to ports 1 and 4, an electric field becomes dominant in the volume, which is called a dominant-E (DE) mode. Similarly, the same magnitude and phase at ports 1 and 4 induce a dominant-H (DH) mode [5,7]. The DE and DH modes are necessary to realise near-field environments with electric and magnetic sources, respectively.…”

“…Since E y is an intended field component, it is preferred that E y remains unchanged irrespective of the slits. However, the unwanted E z should be reduced as much as possible, which cannot be done in the conventional TEM cells reported in [5,7]. As shown in Fig.…”