Electromagnetic Interference Attenuation Research Articles

Electromagnetic shielding material database and machine learning preparing for laser cladding FeCo-based alloy

The compilation and preprocessing of electromagnetic shielding material databases using machine learning techniques are pivotal in contemporary materials science and engineering. These materials play a crucial role in diverse applications such as electronics, telecommunications, aerospace, and automotive industries, necessitating effective attenuation of electromagnetic interference (EMI). This paper underscores the significance of comprehensive databases in organizing material properties systematically, facilitating the identification of novel materials with enhanced shielding effectiveness. It explores the role of machine learning algorithms in predictive modeling and data analysis, expediting the screening process of candidate materials and uncovering hidden correlations within complex datasets. However, the efficacy of machine learning techniques relies heavily on the quality of input data and preprocessing steps. Thus, this paper discusses methodologies for collecting material data, challenges in data curation and integration, and common preprocessing techniques such as data cleaning, feature extraction, and normalization. The integration of electromagnetic shielding material databases with machine learning preprocessing holds great promise for FeCo-based alloy laser cladding manufacturing and design, leading to innovative solutions for electromagnetic interference mitigation across various technological domains.

Multi-Amplification-Channel Active EMI Filter Based on Period Spread-Spectrum PWM for Common-Mode EMI Suppression

Due to the existing coupling loop between the motor drive system and the ground, when switching devices in the drive system operate at a high speed, common-mode (CM)-conducted electromagnetic interference (EMI) is generated in the loop. The electromagnetic environment quality of the motor and peripheral equipment is reduced. As a small and lightweight EMI suppression device, the active EMI filter (AEF) can be used in the motor drive system to suppress the CM-conducted EMI. As the unity gain bandwidth of the operational amplifier (OPAMP) in the AEF is fixed, the CM-conducted EMI suppression effect of the AEF is poor. To solve this problem, the multiple-amplification-channel method is used to spread the frequency range of the CM voltage that the AEF can sense; therefore, the frequency of the compensation current output using the AEF is more complete, and a better CM-conducted EMI attenuation effect is obtained. At the same time, a combination of the period frequency carrier modulation (PCFM) and the multi-amplification-channel AEF is adopted so that the CM-conducted EMI in the whole EMI frequency range of the motor drive system is effectively suppressed.

Influence of carbon nanofiller geometry on EMI shielding and electrical percolation behaviors of polymer composites

The effects of carbon nanofiller geometry on the electrical percolation behavior, electromagnetic interference (EMI) attenuation, and EMI attenuation mechanisms of polymer composites were investigated. Polylactic acid (PLA) filled with carbon nanotubes (CNT), graphene nanoplatelets (GNP), or a hybrid mixture of CNT:GNP were prepared by melt mixing to formulate composites of random nanofiller dispersion and distribution states. The CNT-based composite showed higher EMI attenuation performance and electrical conductivity than the GNP-based and CNT:GNP-based composites. In addition, the CNT-based composite showed a higher ability to attenuate the EMI by absorption than the GNP-based and CNT:GNP-based composites. It is speculated that fiber-like geometry and the smaller surface area of CNT compared to GNP have reduced the reflection of the radiation at the composite external surface and facilitated the dissipation of radiation by absorption due to the effective 3D network within the PLA matrix.

Enhanced Impedance Measurement to Predict Electromagnetic Interference Attenuation Provided by EMI Filters in Systems with AC/DC Converters

Due to the widespread integration of renewable energy sources connected to AC and DC power systems by means of power electronics converters, electromagnetic noise propagates along lines, and metallic earth-return structures. EMI filters are commonly used to mitigate the common mode and differential mode noise at the interface of distribution lines, and their suppression characteristics are usually assessed in standard test setups, the impedances of which are, however, scarcely representative of real-world applications. In this paper, an online, inductively coupled impedance measurement method is proposed. A sensitivity analysis to highlight the benefits of the proposed setup and experimental verification is performed. The proposed method enables non-intrusive impedance measurement in energized systems, including power converters. These measures, in turn, allow the evaluation of modal insertion losses of EMI filters in real-world operating conditions. The three-phase example considered in this study shows significant deviations from manufacturer specifications, thus justifying the need for more advanced estimation techniques.

Comparative Study of Graphene Nanoplatelets and Multiwall Carbon Nanotubes-Polypropylene Composite Materials for Electromagnetic Shielding.

Graphene nanoplatelets (GNPs) and multiwall carbon nanotubes (CNTs)-polypropylene (PP) composite materials for electromagnetic interference (EMI) shielding applications were fabricated as 1 mm thick panels and their properties were studied. Structural and morphologic characterization indicated that the obtained composite materials are not simple physical mixtures of these components but new materials with particular properties, the filler concentration and nature affecting the nanomaterials’ structure and their conductivity. In the case of GNPs, their characteristics have a dramatic effect of their functionality, since they can lead to composites with lower conductivity and less effective EMI shielding. Regarding CNTs-PP composite panels, these were found to exhibit excellent EMI attenuation of more than 40 dB, for 10% CNTs concentration. The development of PP-based composite materials with added value and particular functionality (i.e., electrical conductivity and EMI shielding) is highly significant since PP is one of the most used polymers, the best for injection molding, and virtually infinitely recyclable.

2D Monolayers for Superior Transparent Electromagnetic Interference Shielding.

With countless modern technologies utilizing wireless communication, materials that can selectively allow transmission of visible light and prevent transmission of low frequency GHz electromagnetic interference (EMI) are needed. Recently, 2D materials such as graphene, transition metal dichalcogenides, and MXenes have shown promise for such applications. Despite the rapid advances, little progress has been made in identifying 2D monolayers with intrinsically higher visible transmittance (Tvis) and shielding effectiveness (SE). With endless variations in structure and composition, the 2D materials space is too large for systematic experimental investigation. To tackle this challenge, we perform a high-throughput computational screening. Using an atomistic first-principles method, we simultaneously calculate Tvis and SE of 7000 2D monolayer materials. We identify 26 monolayer materials with excellent properties of >98% Tvis and >5 dB SE (∼70% EMI attenuation). The top candidate, an AgSe2 monolayer with predicted 98.53% Tvis and 12.53 dB SE (∼94% EMI attenuation), is a significant improvement over the state-of-the-art, graphene, with 96.7% Tvis and 3.04 dB SE (∼40% EMI attenuation). Additionally, we gain physical insights into the transparent EMI shielding performance of 2D monolayers and their electronic structure, elucidating the role of surface terminations and nearly free electron states.

Analysis and Suppression of Conducted Common-Mode EMI in WBG-Based Current-Source Converter Systems

The adoption of wide bandgap (WBG) devices in power converters creates challenging conducted common-mode (CM) electromagnetic interference (EMI) issues due to their fast-switching transients and high switching frequencies. This article focused on the analysis and suppression of CM EMI for WBG-enabled three-phase current-source converters (CSCs) consisting of back-to-back rectifier and inverter stages, which have received little attention in the literature. The baseline time-domain waveforms and CM EMI of CSC have been experimentally characterized, showing that even though CSCs have high-quality sinusoidal input–output voltage and current waveforms, their CM EMI still exceeds existing EMI standards. To suppress the CM EMI, the effects of adding different EMI filters at different locations in the CSC topology are evaluated. Based on CSC’s circuit operation and analytical derivation, a CM EMI equivalent circuit (EQC) is proposed for the back-to-back CSC configuration. The proposed EQC achieves fast and accurate CM EMI estimation for CSC using different filtering techniques. Based on the proposed EQC and evaluations of different filter methods, an effective filtering scheme is proposed for the CSC that achieves significant CM EMI attenuation throughout the frequency range from 150 kHz to 30 MHz.

Influence of graphene nanoplatelets geometrical characteristics on the properties of polylactic acid composites

The influence of graphene nanoplatelets (GNP) surface area and size on the dispersion, electrical percolation behavior, electrical conductivity, thermal conductivity, electromagnetic interference (EMI) attenuation, and EMI attenuation mechanisms of GNP/polylactic acid (PLA) were investigated. The GNP/PLA composite's electrical percolation threshold decreased with the increase in GNP surface area and decrease in GNP size. The higher number of GNP particles associated with the decrease in GNP size and increase in GNP surface area facilitated the creation of a conductive network at a lower GNP content. However, at a GNP loading of 30 wt%, the GNP/PLA composites' electrical, EMI SE, and thermal conductivity decreased with the increase in GNP surface area and decrease in GNP size. At high nanofiller loading, the contact resistance between the nanofiller particles is more important than the nanofiller aspect ratio or size. The smaller filler size means more particles and more filler/filler resistance points. The most exciting finding is the dependence of EMI attenuation mechanisms on the GNP surface area. EMI attenuation by absorption was found to increase with the increase in GNP surface area.

Greatly Enhanced Electromagnetic Interference Shielding Effectiveness and Mechanical Properties of Polyaniline-Grafted Ti3C2Tx MXene–PVDF Composites

Nowadays, evolutions in wireless telecommunication industries, such as the emergence of complex 5G technology, occur together with massive development in portable electronics and wireless systems. This positive progress has come at the expense of significant electromagnetic interference (EMI) pollution, which requires the development of highly efficient shielding materials with low EM reflection. The manipulation of MXene surface functional groups and, subsequently, incorporation into engineered polymer matrices provide mechanisms to improve the electromechanical performance of conductive polymer composites (CPCs) and create a safe EM environment. Herein, Ti3C2Tx MXene nanoflakes were first synthesized and then, taking advantage of their abundant surface functional groups, polyaniline (PA) nanofibers were grafted onto the MXene surface via oxidant-free oxidative polymerization at two different MXene to monomer ratios. The electrical conductivity, EMI shielding effectiveness (SE), and mechanical properties of poly (vinylidene fluoride) (PVDF)-based CPCs at different nanomaterial loadings were then thoroughly investigated. A very low percolation threshold of 1.8 vol % and outstanding electrical conductivities of 0.23, 0.195, and 0.17 S/cm were obtained at 6.9 vol % loading for PVDF-MXene, PVDF-MX2AN1, and PVDF-MX1AN1, respectively. Compared to the pristine MXene composite, surface modification significantly enhanced the EMI SE of the PVDF-MX2AN1 and PVDF-MX1AN1 composites by 19.6 and 32.7%, respectively. The remarkable EMI SE enhancement of the modified nanoflakes was attributed to (i) the intercalation of PA nanofibers between MXene layers, resulting in better nanoflake exfoliation, (ii) a large amount of dipole and interfacial polarization dissipation by constructing capacitor-like structures between nanoflakes and polymer chains, and (iii) augmented EMI attenuation via conducting PA nanofibers. The surface modification of the MXene nanoflakes also enhanced the interfacial interactions between PVDF chains and nanoflakes, which resulted in an improved Young's modulus of the PVDF matrix by about 67 and 46% at 6.9 vol % loading for PVDF-MX2AN1 and PVDF-MX1AN1 composites, respectively.

EMI Attenuation in a DC–DC Buck Converter Using GaN HEMT

A dc-dc buck converter using gallium nitride (GaN) high electron mobility transistors (HEMTs) is experimentally investigated at the discontinuous-current-mode (DCM) and the triangular-current-mode (TCM) operations. The objective of this article is to specify the power conversion efficiency and attenuation of common-mode (CM) and differential-mode (DM) noise voltage, measured at the line impedance stabilization network (LISN) for the compared control strategies. Zero-voltage switching achieved for the TCM operation improves efficiency with reference to the DCM operation. However, significant attenuation of electromagnetic interference (EMI) spectra is obtained for TCM operation with capacitive snubber. Sizing of capacitor snubber dependent on parasitic inductances of the commutation circuit and rapid switching of GaN HEMTs are illustrated.

Investigation on the structural quality dependent electromagnetic interference shielding performance of few-layer and lamellar Nb2CTx MXene nanostructures

Tunable Electromagnetic Interference (EMI) shielding behaviors of 2D MXene (Nb2CTx) were explored via different exfoliation conditions. Stacked, lamellar few-layer, oxygen-related surface functional groups, and structural defects along with oxidative products of Nb2CTx were identified by tuning chemical etching conditions during one-step exfoliation process. Exfoliation of Nb2CTx with a tightly packed stacked structure remarked at lower etching times. The unpacking of Nb2CTx into lamellar morphology followed by separated few-layer Nb2CTx remarked at moderate etching time, whereas structural misalignment, defects, and oxidation of Nb2CTx occurred during prolonged chemical etching times. Synergistic effect of one-step extracted few-layers and lamellar structured Nb2CTx favorably enrich the assembly of multiple electrical conductive pathways responsible for absorption dominated EMI shielding performance in X- and Ku-band region. The assembled wax nanocomposites with 80% of Nb2CTx loading exfoliated at 100 h etching time at a thickness of 1 mm exhibited EMI shielding effectiveness of about 44.09 ± 1.99 dB at 12 GHz, and its EMI attenuation mechanism explained by conduction and eddy current loss. The combined action of few-layer and lamellar Nb2CTx nanostructures could be interesting for making novel shielding materials; open a new avenue for niobium series in the MXene family for elaborated applications.

EMC Modeling and Conducted EMI Analysis for a Pulsed Power Generator System Including an AC–DC–DC Power Supply

High-voltage (HV) pulsed power generators are very important in plasma generation in corona discharge reactors. With the advent of new fast switches technologies such as silicon carbide (SiC) and gallium nitride (GaN), electromagnetic interference (EMI) noise in such systems are very challenging. In this article, electromagnetic compatibility (EMC) modeling and conducted EMI analysis for a pulse generator including an ac-dc-dc power supply are developed. Moreover, the common mode (CM) EMI noise propagation through the system is discussed and the noise sources and effect of each component on the noise flowing are analyzed. The ac-dc-dc power supply role is also investigated and since there is an isolation stage in the system, the effect of high-frequency (HF) transformers that provide a flowing path for noise is also studied. In addition, the CM impedance of different parts of the system as well as the noise voltage are discussed by regarding different values for parasitic parameters of the system. As the system noise level could not meet IEC61800-3 standard, EMI attenuation techniques were applied to the system. By using balance technique and adding filtering inductor as a decoupling inductance, the EMI noise is reduced. Furthermore, an EMI filter optimized and designed for the power supply system that could reduce the EMI noise level. However, by using some EMI reduction techniques that are explained in this article, the size of the required EMI filter is reduced. In this article, EMC modeling, conducted EMI analysis, and EMI reduction techniques led to higher performance and efficiency and lower size of EMI filter that reduced the overall size of the system.

Exfoliation and Defect Control of Two-Dimensional Few-Layer MXene Ti3C2Tx for Electromagnetic Interference Shielding Coatings.

Defect-controlled exfoliation of few-layer transition-metal carbide (f-Ti3C2Tx) MXene was demonstrated by optimizing chemical etching conditions, and electromagnetic interference (EMI) shielding coatings were explored. The structural features such as layer morphology, lateral size, layer thickness, defect density, and mechanical stability of the exfoliated f-Ti3C2Tx were strongly dependent on exfoliation conditions. By selecting appropriate exfoliation conditions, moderate etching time leads to the formation of quality f-Ti3C2Tx with lesser defects, whereas longer etching time can break the layer structure and increase defect density, structural misalignment, and oxidative products of f-Ti3C2Tx. The resultant fabricated free-standing flexible f-Ti3C2Tx films exhibited electrical conductivity and electromagnetic interference (EMI) shielding effectiveness (SE) in the X-band of about 3669 ± 33 S/m and 31.97 dB, respectively, at a thickness of 6 μm. The large discrepancy in EMI SE performance between quality (31.97 dB) and defected (3.164 dB) f-Ti3C2Tx sheets is attributed to interconnections between f-Ti3C2Tx nanolaminates interrupted by defects and oxidative products, influencing EMI attenuation ability. Furthermore, the demonstrated solution-processable high-quality f-Ti3C2Tx inks are compatible and, when applied for EM barrier coating on various substrates, including paper, cellulose fabric, and PTFE membranes, exhibited significant EMI shielding performance. Moreover, controlling defects in f-Ti3C2Tx and assembly of heterogeneous disordered carbon-loaded TiO2-Ti3C2Tx ternary hybrid nanostructures from f-Ti3C2Tx by tuning etching conditions could play an enormous role in energy and environmental applications.

Excellent electromagnetic interference shielding characteristics of a unidirectionally oriented thin multiwalled carbon nanotube/polyethylene film

In this study, we synthesized oriented multiwalled carbon nanotube (CNT)/polyethylene (PE) composite films and investigated their electromagnetic interference (EMI) shielding properties. The oriented CNT sheet structure was prepared by stacking CNT webs produced by a dry spinning technique with a CNT forest. In a near-field EMI attenuation measurement by a microstrip line method, composite films with a CNT fraction higher than 2 wt% showed a high attenuation that exceeded 50 dB at 10 GHz. This high attenuation was due to the enhanced magnetic anisotropy of the oriented CNTs and the encapsulated catalyst-derived cementite nanoparticles. This is the first report of high magnetic anisotropy in an oriented CNT structure for noise attenuation in a transmission line. In a far-field EMI shielding measurement by a coaxial tube method, the EMI shielding effectiveness (SE) significantly increased as the number of CNT web layers increased. A CNT/PE film with a high CNT fraction was found to have a high specific EMI SE of 0.6 dB/μm. The oriented CNT/PE composite film has great potential as a promising EMI material that demonstrates high shielding efficiency performance with low CNT loading.

Adaptive analogue calibration technique to compensate electrode motion artefacts in biopotential recording

This study presents an adaptive analogue calibration method to compensate electrode–skin impedance mismatch during biopotential signal (electrocardiogram, electroencephalogram and electromyogram) acquisition with enhanced immunity to electromagnetic interference (EMI). The method continuously measures the variation of the impedance mismatch between the electrode–skin interfaces arising primarily due to motion artefacts, and thereafter compensate for the resulting distortions at the output. The compensation is done with the help a proportional–integral–derivative controller in the feedback loop, together with the acquisition of the biopotential signals. A common mode shunt feedback at the output attenuates the common mode EMI and reduces the common mode deviation. As compared to previously reported techniques, the proposed technique refutes any need for offline manual calibration and shows a significant improvement in EMI attenuation without interrupting the main system's operation. This study explains the proposed technique with the comprising blocks, illustrates the theoretical models and analyses, and evaluates the superior performances of the proposed method by comparing the responses with those obtained from the other EMI-Immune electrode mismatch compensating front-ends existing in the literature.

The Conducted Emission Attenuation of Micro-Inverters for Nanogrid Systems

Road lighting systems require a significant amount of electric energy. To compensate for the utilized energy, the concept of a nanogrid road lighting system is presented. A solar panel is installed on the top of a lighting pole to generate electric power. In this research, a photovoltaic simulator (PV simulator), which is used to simulate solar behavior such as current, voltage, and power based on temperature and solar irradiance levels, is employed to replace a solar panel. In the nanogrid system, grid-connected and stand-alone micro-inverters are employed to convert the electric power. The inverters comprise switching devices that can generate electromagnetic interference (EMI) when operating, which is harmful to the grid system and the electrical equipment. In general, EMI has been studied and reduced in electrical appliances, which only receive electric power. However, for the nanogrid system, which supplies electricity to the grid system, there is less study on the EMI topic because the usage is still not widespread. In the future, the nanogrid system will be widely used delivering high power directly into the electrical grid system. Therefore, the study and attenuation of EMI in the nanogrid system are very promising. Conducted emission (CE) is one form of EMI that flows through a cable connecting several appliances in the frequency range of 150 kHz to 30 MHz. CE of grid-connected and stand-alone micro-inverters have high levels in the low-frequency range between 150 kHz–5 MHz and then decreases steadily. CE attenuation is important for this inverter in a solar power system. This research studies the effect of CE mitigation on the nanogrid system. The result is compared with the Comité International Spécial des Perturbations Radio (CISPR) 14-1 standard. Finally, the passive EMI filter can reduce CE and meets the CISPR 14-1 standard.

2D Ti3C2Tx MXene/polyvinylidene fluoride (PVDF) nanocomposites for attenuation of electromagnetic radiation with excellent heat dissipation

The present study deals with novel, and cost-effective preparation of 2D MXene (Ti3C2Tx) filled polyvinylidene fluoride (PVDF) polymer nanocomposite for the attenuation of electromagnetic interference (EMI). The obtained nanocomposite showed remarkable shielding effectiveness (SE) of 48.47 ± 3.5 dB for 22.55 vol% filler contents at a thickness of 2 mm. Formation of conducting network along with the assembly of micro capacitor network preserved for its high EMI shielding performance. The absorption dominated EMI shielding mechanism explained by the strong resonance, and interfacial polarization favors the loss of incident EM energy confirmed from dielectric measurements. Besides, the enhanced thermal conductivity of MXene-PVDF nanocomposites about 0.767 ± 0.034 Wm−1K−1 at 22.55 vol% filler content depicts that a large amount of incident EM wave attenuated majorly by dielectric components which would be dissipated as heat quickly. The fabricated MXene-PVDF nanocomposites could be a potential candidate for EMI shielding materials and promising multifaceted electronic utilization.

Integrated Magnetic Circuits for Differential-mode and Common-mode Chokes of EMI Filters


 In this paper, two magnetic circuits to integrate common-mode (CM) and differential-mode (DM) chokes of an electromagnetic interference (EMI) filter are proposed. The DM and CM chokes are integrated by using UIU and EI ferrite core shapes. To evaluate the EMI reduction performances of proposed approaches, the conducted EMI reduction performances of proposed integrated DM and CM chokes are compared with the conventional CM choke and traditional separated DM and CM chokes. From the experimental results, it ensures the advantages of the use of proposed approaches. Although some magnetic parts are eliminated by proposed approaches, the amount of DM and CM EMI attenuation rate is comparable to the case of traditional separated DM and CM chokes, except the highest peak is located at different frequencies.

Power Efficiency and EMI Attenuation Optimization in Filter Design

This paper presents a discrete conducted electromagnetic (EM) interference filter optimization procedure, based on a genetic algorithms. A macromodeling technique taking into account the load impedance, the source emissions and the filter parasitic components, including the filter layout, is used to obtain an accurate solution for the optimization process. The latter searches among supplier passive component databases and provides, for a given filter topology, an optimal set of components available on the market. This approach has been applied to a differential Class-D audio amplifier for validation. By considering the electromagnetic interference (EMI), the additional power losses introduced by the filter and the audio gain, two different optimization formulations have been tested. The first corresponds to maximizing the power efficiency of the system while respecting a determined level of EM emissions. The second corresponds to minimizing the EMI without exceeding a determined level of power loss. The optimized filters are built and measurements are carried out. The results show a remarkable power efficiency improvement and a significant EM emission reduction when compared to a reference filter.

Electromagnetic interference attenuation and shielding effect of quaternary Epoxy-PPy/Fe3O4-ZnO nanocomposite as a broad band microwave-absorber

An increase in the electromagnetic wave pollution generated from wireless telecommunication devices has devoted to a great request for exploiting microwave absorbing materials for themselves. The combination of inherently conducting polymers such as polypyrrole (PPy) with metal oxides has led to design ideal microwave absorbing materials which benefit both advantage effects of ICPs and metal oxide nanoparticles. Herein, the quaternary nanocomposite of Epoxy-PPy/Fe3O4-ZnO was prepared and tested for the absorption of X-band microwaves. Simultaneous application of metal oxides and conducting polypyrrole in the epoxy matrix was evaluated in order to increase the absorption intensity and broadness of microwaves in X-band region. The morphology, microstructure, and phase structure of Fe3O4, ZnO, and PPy, as well as quaternary nanocomposite were characterized and studied using FTIR, XRD, FESEM and TEM techniques. The presence of nanoparticles in the quaternary nanocomposite was confirmed by EDS. The magnetization of iron oxide was studied by VSM. The synergetic effect of iron oxide and zinc oxide nanoparticles in different weight ratios (Fe3O4/ZnO) on the electromagnetic wave absorption was evaluated. The electromagnetic parameters have been evaluated by the vector network analyzer in the frequency range of 8.2–12.4 GHz which is named as X-band region and is adequate for radar applications. The electromagnetic wave absorbing outcomes indicated that Epoxy-PPy/Fe3O4-ZnO quaternary nanocomposite has wide absorption area and high attenuation, which is believed to be due to dielectric loss properties related to the polypyrrole, magnetic loss factor of Fe3O4, and synergetic effects of components. The maximum reflection loss reached to −32.53 dB at 9.96 GHz with a nanocomposite thickness of 2 mm which is dedicated to the Epoxy-PPy/Fe3O4-ZnO with iron oxide to zinc oxide ratio of 2:1. The absorption bandwidth with the reflection loss lower than −10 dB (90% attenuation) was up to 4.2 GHz that covering a frequency range of 8.2–12.4 GHz. Results showed that absorber having %15 (w/w) polypyrrole/epoxy resin in Epoxy-PPy/Fe3O4-ZnO nanocomposite with iron oxide to zinc oxide ratio of 2:1 displays the best reflection loss properties. The loss curves illustrated the values of dielectric loss tangent and magnetic loss tangent of prepared nanocomposites which are in the range of 0.25–0.7 and −0.08 to 0.09 respectively. Therefore, microwave absorption mechanism is probably attributed to dielectric loss.