The gap of standardization for conducted and field coupled electromagnetic interferences (EMI) in the 2–150 kHz frequency range can lead to Electromagnetic Compatibility (EMC) problems. This is caused by power systems such as Pulse Width Modulation (PWM) controlled rectifiers, photovoltaic inverters or charging battery units in electric vehicles. This is a very important frequency spectral due to interferences generated in a wide range of devices and, specifically, communication problems in the new technologies and devices incorporated to the traditional grid to convert it into a Smart Grid. Consequently, it is necessary to provide new solutions to attenuate this kind of interference, which involves finding new materials that are able to filter the electromagnetic noise. This contribution is focused on characterizing the performance of a novel material based on nanocrystalline and comparing it to most common material compositions such as MnZn and NiZn. This research is carried out from the point of view of the manufacturing process, magnetic properties and EMI suppression ability. This last item is carried out through two analysis procedures: a theoretical method by determining the attenuation ratio by measuring impedance parameter and proposing a new empirical technique based on measuring directly the insertion loss parameter. Therefore, the main aim of this characterization process is to determine the performance of nanocrystalline compared to traditional cable ferrite compositions to reduce the interferences in this controversial frequency range. From the results obtained, it is possible to deduce that nanocrystalline cable ferrite provides the best performance to filter the electromagnetic noise in the 2–150 kHz frequency range.

Magnetic near-field probes (NFP) represent a suitable tool to measure the magnetic field level from a small electromagnetic interference (EMI) source. This kind of antenna is useful as a magnetic field probe for pre-compliance EMC measurements or debugging tasks since the user can scan a printed circuit board (PCB) looking for locations with strong magnetic fields. When a strong H-field point is found, the designer should check the PCB layout and components placement in that area to detect if this could result in an EMI source. This contribution focuses on analyzing the performance of an easy to build and low-cost H-field NFP designed and manufactured using a standard PCB stack-up. Thereby, the frequency range and sensitivity of the NFP-PCB are analyzed through a Finite Element Method (FEM) simulation model that makes it possible to evaluate its sensibility and effective frequency range. The numerical results obtained with the FEM models are validated against measurements to verify the design and performance of our NFP. The FEM model reproduces the experimental procedure, which is used to evaluate the performance of the NFP in terms of sensitivity by means of the simulated near-field distribution. The NFP-PCB has almost a flat response from 180 MHz to 6 GHz, with an almost perfect concordance between numerical and experimental S21 results. The numerical results show an average transmission loss of −27.9 dB by considering the flat response bandwidth, whereas the experimental one is −29.7 dB. Finally, the designed NFP is compared to two high-quality commercial probes in order to analyze its performance.

The reduction of embedded portable devices involves a magnetic field interference problem when it integrates near field communication (NFC) due to the presence of conductive surfaces, such as ground planes, batteries, or metallic enclosures. Flexible sintered ferrite sheets (FSFS) represent an interesting shielding solution to prevent electromagnetic interferences problems related to NFC, thanks to their ability to control the magnetic flux. The characterization of FSFS effectiveness is analyzed as a function of the sheet thickness in this contribution. This is performed with the aim of determining which is the optimum thickness value to retune an NFC antenna to its original operation frequency value (13.56 MHz) when it is affected by a near conductive surface. A finite element method simulation model is designed and corroborated with the experimental results to evaluate the performance of different FSFS thicknesses in terms of resonant frequency shift, magnetic field strength, and communication distance. An electromagnetic scanner is also used to determine the ability of the best FSFS thickness to shield an NFC transmitter antenna when a battery is set under it, emulating a usual problem. The results obtained show that the magnetic field strength is significantly attenuated and the communication distance is highly shorted. Therefore, besides selecting a material that provides high reflection and low losses at 13.56 MHz, thickness must be considered to ensure the greatest communication effectiveness. Consequently, the use of a wrong FSFS thickness could lead to shifting the resonance frequency to lower values than expected, detuning the communication.

Electromagnetic noise absorber sheets have become a solution for solving complex electromagnetic interference (EMI) problems due to their high magnetic losses. This contribution is focused on characterizing a novel structure that is based on an absorber film with a metal layer attached on its top side. Two different absorber compositions were combined with Al and Cu metal layers in order to study the improvement on the performance of these structures, depending on the complex permeability, absorber film thickness, and type of metal. The transmission attenuation power ratio of the absorber films is analyzed and compared to the performance of absorber and metal structures. The measurement procedure is carried out attaching the films into a microstrip line that has been designed based on IEC standard (IEC 62333-2). This test fixture is employed as a transmission line to simulate a general noise path. The performance of absorber composites to filter electromagnetic noise is evaluated through analyzing S₂₁ and S₁₁ parameters. This is carried out with the aim of finding out in which conditions the absorption loss is improved when a metal layer is attached. In addition, the possible re-radiation effect, due to the magnetic field that is generated by the eddy currents induced in the metal layer, is examined.

The study and measurement of the shielding effectiveness (SE) of planar materials is required to predict the suitability of a certain material to form an enclosed electromagnetic shield. One of the most widely used standards for measuring the SE of planar materials is ASMT D4935-18. It is based on a coaxial sample holder (CSH) that operates up to 1.5 GHz. Due to this standard’s frequency limitations, new variants with higher frequency limits have been developed by decreasing the size of the CSH conductors and the samples. However, this method and its high-frequency variants require two types of samples with very specific geometries and sizes. This method is unsuitable for certain types of nanomaterials due to their complex mechanization at such undersized scales. This contribution proposes an alternative SE measurement method based on an absorber box that mitigates the problems presented by the ASTM D4935-18 standard. The SE of rigid nanomaterial samples based on several concentrations of multi-walled carbon nanotubes (MWCNT) and two different fiber reinforcements have been obtained.

The ideal procedure to start designing an electronic device is to consider the electromagnetic compatibility (EMC) from the beginning. Even so, EMC problems can appear afterward, especially when the designed system is interconnected with external devices. Thereby, electromagnetic interferences (EMIs) could be transmitted to our device from power cables that interconnect it with an external power source or are connected to another system to establish wired communication. The application of an EMI suppressor such as a sleeve core that encircles the cables is a widely used technique to attenuate EM disturbances. This contribution is focused on the characterization of a variation of this cable filtering solution based on openable core clamp or snap ferrites. This component is manufactured by two split parts pressed together by a snap-on mechanism which turns this into a quick, easy to install solution for reducing post-cable assembly EMI problems. The performance of three different materials, including two polycrystalline (MnZn and NiZn) materials and nanocrystalline (NC) solution, are analyzed in terms of effectiveness when the solid sleeve cores are split. The possibility of splitting an NC core implies an innovative technique due to the brittleness of this material. Thus, the results obtained from this research make it possible to evaluate this sample’s effectiveness compared to the polycrystalline ones. This characterization is carried out by the introduction of different gaps between the different split-cores and analyzing their behavior in terms of relative permeability and impedance. The results obtained experimentally are corroborated with the results obtained by a finite element method (FEM) simulation model with the aim of determining the performance of each material when it is used as an openable core clamp.