GHz X-band Research Articles

High-Gain Multi-Band Koch Fractal FSS Antenna for Sub-6 GHz Applications

This study introduces a novel antenna based on the binary operation of a modified circular patch in conjunction with the Koch fractal. The antenna is intended for applications in the sub-6 GHz band, partial C-band, and X-band. The low-cost antenna is fabricated on a 1.6-mm-thick FR-4 substrate. A frequency-selective surface (FSS) is used to overcome the decreased values of the gain and bandwidth due to the fractal operations. The introduced split ring resonator (SRR) and the antenna substrate dimension reduction reduce the bandwidth and antenna gain. The air gap between the FSS and the antenna not only enhances the antenna gain but also controls the frequency tuning at the design frequency. The antenna size is miniaturized to 36.67%. A monopole antenna ground loaded with an SRR results in improved closest tuning (3.44 GHz) near the design frequency. The antenna achieves a peak gain of 9.37 dBi in this band. The FSS-based antenna results in a 4.65 dBi improvement in the gain value with the FSS. The measured and simulated plots exhibit an excellent match with each other in all three frequency bands at 2.96–4.72 GHz. These bands cover Wi-MAX (3.5 GHz), sub-6 GHz n77 (3300–3800 MHz), n78 (3300–4200 MHz), and approximately n79 (4400–4990 MHz), in addition to C-band applications.

Design and experimental investigation of an origami inspired X-band accordion waveguide

This paper presents design, numerical analysis and experimental investigation of an origami inspired X-band accordion waveguide that is aimed to create a flexible and adaptive solutions. The design process is conducted in a Finite Integration Technique (FIT) based microwave simulation software to model and simulate the proposed waveguide, and that shows structural benefits of origami technique based paper folding. Proposed waveguide model is numerically analyzed under both X and Y bending with 30˚, 60˚, 90˚ and 120˚ bending angle to provide its flexibility. Besides, the electric and magnetic field distributions were also obtained and explained in details to provide working mechanism of the proposed accordion waveguide. The S21 transmission characteristics between ports exhibits a decrease of 0.015 dB in numerical results, which is negligible and acceptable in applications. The experimental results demonstrate that the proposed waveguide has effective transmission characteristics within the 8–12 GHz X-band frequency range, with a satisfactory S21 transmission parameter. The numerical and experimental results show that proposed origami inspired accordion waveguide has a huge potential for application in dynamic microwave and satellite components.

Influence of Dy3+ doping on Mössbauer, magnetic and microwave absorption properties of M-type Ba0.5Ca0.5DyxFe12-xO19 hexaferrites

The present research paper reports a systematic study of the magnetic, and structural properties of Ba0.5Ca0.5DyxFe12-xO19 M-type hexaferrite. The dysprosium was doped @ x = 0 − 0.2, keeping Δx = 0.05, in BCDF by the sol–gel self-ignition technique. The sintering of the synthesized samples was performed for 4 h at 1050°C. The crystallographic analysis of the samples was made from the X-ray diffractograms (XRD), while the morphological and elemental analysis was made from field emission scanning electron microscopy (FESEM), and energy-dispersive X-ray spectroscopy (EDAX) profiles. The structural results revealed the formation of the M-type hexaferrite having P63/mmc as a space group along with the co-existence of a secondary Fe2O3 phase. FESEM micrographs exhibit the hexagonal platelets randomly arranged with agglomerations at some places giving rise to the random variations in particle size with varying ’x’. Magnetic measurements (VSM) show that the saturation magnetization (MS) and coercivity (HC) increase with the increasing Dy3+ doping pointing towards the fact that the Dy doping in Ba-Ca ferrite can be used to fabricate the hard ferrites with good saturation magnetization. The Mössbauer spectrum recorded at room temperature reveals five superimposed sextets representing the five Fe3+ ion sites. Investigating the Microwave absorption (MWA) characteristics in the frequency range 8 − 12 GHz (X-band), reveals that the sample with x = 0.1 having 3 mm thickness possesses good MWA power. Its minimum RL value for matching frequency 10.06 GHz is approximately −26.96 dB, indicating that more than 90 % of microwaves are absorbed. The current work offers the Dysprosium-doped BCDF hexaferrites, as promising candidatesfor microwave absorption applications.

Study on the influence of nickel-iron alloy powder on the mechanical strength and electromagnetic shielding effectiveness of iron ore tailings/cement composite

Effective electromagnetic interference shielding has become a focal point of concern for special construction and buildings. In this study, a novel cement-based electromagnetic shielding composite material was developed by the incorporation of both nickel-iron alloy powder (NF) and the partial replacement of the fine sand portion of ISO standard sand with iron ore tailings (IOTs). Experimental results indicate that the electromagnetic shielding performance of the cement/IOTs composites was improved with the increasing NF content at frequencies ranging from 8.2 to 12.4 GHz (X-band) while their mechanical properties changed little. With the incorporation of 5 % NF in the cement mortar, a maximum of 22.17 dB at 12.4 GHz could be achieved. Further analysis of the shielding mechanism of this composite material reveals that the enhancement of its electromagnetic shielding efficiency mainly results from the absorption loss rather than reflection loss.

Dielectric resonator antenna with square slot dgs and amc support for gain enhancement

A miniatured Dielectric Resonator Antenna (DRA) designed on Defected ground structure (DGS) with backing of Artificial Magnetic Conductor (AMC) is presented in this work. The designed antenna showing wide bandwidth to cover WLAN, Wi-Fi and 5G communication applications under sub 6 GHz range and X-band for satellite communication device applications. Antenna occupying the dimension of 35 × 30 × 1.6 mm on Rogers RT-duroid 5880 substrate material, DRA on alumina material of permittivity 9.8 with dimension of 25 × 20 × 10 mm and the AMC surface of dimension 60 × 58 × 1.6 mm on FR4 substrate material. The constructed antenna resonating in the wide band from 3.4–11.5 GHz by holding overall bandwidth of 8.11GHz and an impedance bandwidth of 139%. The DRA placed over the antenna providing the axial ratio at two bands of 4.2–6 GHz and 9.2 to 11.4 GHz with axial bandwidth of 36% and 28% respectively. The placement of AMC structure beneath the antenna exhibiting an improvement in gain of 9% and an average gain attained in the operating band is around 7.2 dBi. The unique combination of monopole antenna with DRA and AMC providing excellent bandwidth, axial ratio and gain.

Electromagnetic Interference Shielding Properties of SrFe12-2x(Cu0.5Co0.5Ti)xO19 Hexaferrite

Electromagnetic (EM) pollution has become one of the most severe forms of pollution for humans and electronic devices. In order to protect humans and electronic devices from electromagnetic interference (EMI), the material that could shield the EMI should be considered. Hexagonal ferrites are considered as promising candidates for EMI shielding materials. This work fabricated Cu, Co, and Ti co-doped SrFe12O19 (SrFe12–2x(Cu0.5Co0.5Ti)xO19) samples to investigate EMI shielding properties. Among the samples, the doped ones exhibited better EMI shielding performance than the undoped one, which could be judged through total shielding efficiency (SET). In addition, the samples exhibited the best shielding performance in the frequency range of 8–12 GHz (X-band), with the best value of SET = 4.20 dB for the x = 0.20 sample, which could block ~62% of the incident microwave. The x = 0.05 sample also exhibited similar values with SET = 4.17 dB. The enhancement of SET values for doped samples compared to the undoped one could be attributed to the increase in conductivity caused by doping. In addition, the enhancement of SET could also be attributed to the effects of the magnetic dipoles combined with the electric dipoles of ferrites.

Lan+1NinO3n+1 (n = 1, 2, 3) RP-phases for EMI shielding and ESD applications

Advancements in electronics and digitization have led to concerns about electromagnetic interference (EMI), necessitating effective EMI shielding measures. This study investigates the electromagnetic wave absorption properties of Lan+1NinO3n+1 (n = 1, 2, 3) Ruddlesden-popper (RP) phases. While a single phase, La2NiO4, was obtained for n = 1, mixed phases of La3N2O7-δ/La4Ni3O10-δ were observed for n = 2 and 3. Electron paramagnetic resonance spectroscopy revealed superparamagnetic behavior for La2NiO4 and multi-resonance peaks for La3Ni2O7-δ, suggesting increased surface defects. La3Ni2O7-δ exhibited enhanced absorption properties, with a minimum reflection loss of −19.4 dB and a broader (less than −10 dB) bandwidth covering 4.2 GHz (X-band) at a thickness of 1.4 mm, attributed to optimal conductivity, magnetic resonance, eddy current losses, and synergistic dielectric loss. The sample with n = 2 demonstrates potential for EMI absorption and electrostatic discharge (ESD) applications.

Synthesis of biopolymer blends nanocomposites embedded with mono-(Ag, Fe) and bi-(Ag-Fe) metallic nanoparticles using an eco-friendly approach for antimicrobial activities.

Plant-mediated solution casting is used to develop eco-friendly polymer blend nanocomposites from polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP) doped with Silver (Ag), Ferrous (Fe) monometallic and Silver-Ferrous (Ag-Fe) bimetallic nanoparticles (NPs). These nanocomposites were studied to understand their electromagnetic interface (EMI) shielding efficiency and antimicrobial activities, besides evaluating their physical and chemical properties. The Fourier transform infrared (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and energy dispersive X-ray (EDX) characterization techniques were used to examine the interactions between the polymers, the presence of silver and ferrous particles in the composites, the crystallinity shift, the surface morphology, the shape and size of the nanoparticles and the distribution of the nanoparticles in the composites. The FTIR spectra showed the interactions among the components of the composites. According to XRD spectra, the incorporation of nanoparticles into the PVA polymer significantly reduced the crystalline character of the polymer from 0.38 to 0.24 for the composition consisting of silver and iron nanoparticles in equal proportion. The results from SEM, EDX and XRD corroborate the presence of nanoparticle forms. The thermogravimetric analysis (TGA) tests reveal that the thermal stability of bimetallic composites is greater than that of monometallic composites. The tensile properties showed that the addition of nanoparticles to the PVA/PVP polymer matrix increased its mechanical strength from 59.3MPa to 85.5MPa. We examined its efficacy against Escherichia coli, Staphylococcus aureus and Candida albicans as microorganisms. Good antibacterial and antifungal activity was observed. The bimetallic composites demonstrated greater activity than monometallic composites against these bacterial and fungal species. All bimetallic nanocomposites have shown enhanced, loss due to reflection, loss due to absorption, and the total EMI shielding efficiency at 8GHz (X-band) and 16GHz (Ku-band) frequency. All these results ratify, that these newly developed bio nanocomposites are most suitable in many applications, in EMI shielding, nanotechnology, and medical fields.

CPW-Fed UWB-MIMO Antenna with Triple-band Notched and High Isolation using Double Y-shaped Decoupling Structure

A ultra-wideband (UWB) multiple-input-multiple-output (MIMO) antenna using double Y-shaped decoupling structure with high isolation and triple notched-band is presented. The designed antenna composed of two orthogonally placed monopole elements, coplanar ground and double Y-shaped branch. The defected substrate structure is used to achieve miniaturization. By slotting successively C-shaped slot, semi-circular slot and rectangular slot on the radiation patch and the ground, achieved three notched bands at 3.5 GHz WiMAX, 5.25 GHz WLAN, and 7.5 GHz X-band. The proposed antenna can operate in range of 2.56-12 GHz with triple notched bands of 3.31-3.96 GHz, 4.58-5.67 GHz and 6.57-8.16 GHz. Considering all the results, it can be concluded that the antenna presented has a great performance in terms of good radiation, high isolation (>24 dB), a low level ECC (<0.01) and a high DG level (>9.99), which proves the presented antenna has good prospect in UWB-MIMO systems.

Design and equivalent circuit modelling of super compact ultrathin metamaterial absorber for microwave frequency Regime

Abstract This article is an attempt to design and develop a metamaterial-based microwave absorber with a low profile, broad incidence angle and compactness in the microwave frequency range. Further, equivalent circuit model of the proposed structure is discussed based on circuit theory. The unit cell focuses on achieving maximum absorption at C-, X-, and K-band. The dimensions of the proposed design are ultrathin and compact, having an overall size of 8 mm × 8 mm × 0.8 mm. The dimensions are optimized in such a fashion to achieve three different peaks at three various bands (C, X and K), thereby making the triple-band behaviour of the metamaterial absorber possible. The structure provides absorption of 98.26 % absorption at 7.76 GHz (C-band) while absorption of 96.74 % is achieved at 10.26 GHz (X-band) and 99.92 % absorption at 19.32 GHz (K-band) of microwave regime. The experimental verification of design conform that the measured results are found to be in close agreement to simulated ones.

Design and optimization of a deep learning algorithm assisted stub-loaded dual band four-port MIMO antenna for Sub-6 GHz 5G and X band satellite communication applications

In this article, C-type stubs loaded hexagonal shaped four-element MIMO antenna is proposed with improved isolation for sub-6 GHz 5G and X-band satellite wireless communication applications. Initially, the design and simulation studies of the MIMO antenna are performed using Computer Simulation Software (CST) software but its design parameter estimation and optimization consume higher time using conventional EM simulation tools. In order to solve this issue, Deep Learning algorithm-based approach has been proposed to determine the optimal physical parameters along with best possible performance characteristics. This suggested DL based approach is resource and time efficient for parameter estimation and optimization during the design process. To reduce design space and generation of an effective dataset, the feature reduction method (FRM) is implied during the design process. The S-parameters are predicted through Dual-Channel (DC-DNN) Deep Neural Network model. The dual-band MIMO antenna operates with −10 dB impedance Bandwidths of 40 % (2.8 GHz – 4.2 GHz), 38.41 % (6.1 GHz – 9.0 GHz) and shows excellent diversity performance. The proposed MIMO antenna is suitable for Sub-6 GHz n77 (3.3–4.2 GHz), n78 (3.3–3.8 GHz) 5G NR bands and also supports X band satellite (7.25–7.75 GHz and 7.9–8.4 GHz) communication applications.

Cyclic Disulfide-Bridged Dinitroxide Biradical for Measuring Thiol Redox Status by Electron Paramagnetic Resonance.

Among low-molecular-weight thiols, glutathione (GSH) is the main antioxidant in the cell, and its concentration is an indicator of the redox status. A cyclic disulfide-linked dinitroxide was designed for monitoring GSH by electron-paramagnetic resonance (EPR) spectroscopy. Reaction of the disulfide with GSH and three other thiols was measured at 9.6 GHz (X-band) and shown to be of first order in thiols. It is proposed that the reaction of the disulfide with 1 equiv of thiolate produced a short-lived intermediate that reacts with 1 equiv of thiolate to produce the cleavage product. The equilibrium ratio of the cleaved and intact disulfide is a measure of the redox state. Since the long-term goal is to use the disulfide to probe physiology in vivo, the feasibility of EPR spectroscopy and imaging of the disulfide and its cleavage product was demonstrated at 1 GHz (L-band).

Magnetic carbon fiber/reduced graphene oxide film for electromagnetic microwave absorption

Adding 10 wt% carbon fiber (CF) into graphene oxide (GO) dispersion were performed to fabricate CF10/reduced graphene oxide (rGO) film without the use of surfactants, binders or polymer matrices. The all-carbon CF10/rGO film possesses plausible tensile strength over one page of regular A4 printing paper and improved room-temperature ferromagnetism compared with the as-assembled rGO film, with saturation magnetization of about 0.327 emu/g and coercivity of about 100.4 Oe. The CF10/rGO composite with 50 wt% filler loading exhibits a good electromagnetic wave (EMW) absorption performance in the measured frequency range of 2–18 GHz. A minimal reflection loss reaches −34.3 dB@6.2 GHz (C-band), −35.4 dB@9.6 GHz (X-band), and −33.7 dB@13.1 GHz (Ku-band) with a thickness of 3.0 mm, 2.0 mm and 1.5 mm, respectively. The enhanced complex permittivity and permeability causing by the introduction of CF in rGO film are in favor of achieving an excellent impedance matching characteristic between the carbon materials and the air, responsible for more amount of EMW incidence; furthermore, localized electronic spin states and multi-relaxation processes arisen from the topological defects, oxygen-containing groups, and interfaces are ascribed to the enhanced microwave attenuation ability.

Investigation on Dielectric Properties of Sludge Waste from Water Treatment Using Microwave Non-Destructive Testing (MNDT)

The demand for water cleanup rises in tandem with a country's requirements and development. Recovery of purified water containing nutrients and other beneficial materials is a critical opportunity that must be taken advantage of. A challenge that needs to be tackled is the necessity for large capacity and high-value management of sludge waste following the water treatment process. The pH level and microwave frequencies influence were used as a starting point for assessing the content of the sludge waste. Microwavenon-destructive testing (MNDT) is a microwave measurement that can be used to determine the dielectric characteristics of materials without destroying or modifying the sample's content. The methodology employs a free-space measurement technique with a frequency range of 8 to 12 GHz (X-band). Through S-parameters acquired, a correlation analysis was done to analyze the effect of frequencies with the sludge waste. A comparative investigation with peat soil samples in establishing if the sludge has similar attributes to normal soil is used to ensure the accuracy of the sludge waste data. It can be determined that the sludge waste has a high signal correlation towards the frequency band 8 GHz to 12 GHz, which is compatible with the MNDT approach. All of the sludge samples had a pH range that is appropriate for agricultural use.

Electromagnetic interference shielding behavior of polypyrrole-impregnated poly(ether imide)/sulfonated poly(ether ether ketone) composites

Electromagnetic interference (EMI) shielding materials are of major interest for modern society due to proliferation of electronic instruments and it reports the designing of electromagnetic radiations shielding material against electromagnetic pollution. Here, we prepared a series of composites comprising polyetherimide (PEI) with sulfonated poly(ether ether ketone) (SPEEK) by solvent casting method, having SPEEK loading ranging from 10 to 50 wt%. All the composites and PEI films were impregnated with pyrrole via in situ polymerization method to enhance their electrical conductivity. The morphology of composites was studied by SEM (scanning electron microscopy) and XRD (X-ray diffraction) analysis. Structural and thermal properties were investigated by Fourier-transform infrared spectroscopy (FT-IR), TGA and DSC, respectively. Electrical conductivity was analyzed by two probe method. Maximum conductivity of 2.24*10−4 S/cm was achieved at 50 wt% loading of SPEEK, due to the presence of conductive network between polypyrrole (PPy) and SPEEK throughout PEI matrix. These composites exhibited an average electromagnetic interference SET values up to −21 dB which makes them capable for shielding in the frequency range of 8.2–12.0 GHz (X-band). This study provides an avenue for fabrication of absorption dominating EMI shielding composites, which is promising material for commercial applications in next generation electronic instruments.

Compact Multi-Layered Symmetric Metamaterial Design Structure for Microwave Frequency Applications.

Metamaterial analysis for microwave frequencies is a common practice. However, adopting a multi-layered design is unique in the concept of miniaturisation, thus requiring extensive research for optimal performance. This study focuses on a multi-layered symmetric metamaterial design for C- and X-band applications. All simulation analyses were performed analytically using Computer Simulation Technology Studio Suite 2019. The performances of the proposed metamaterial design were analysed through several parametric studies. Based on the observation, the proposed metamaterial unit cell design manifested resonant frequencies at 7.63 GHz (C-band) and 9.56 GHz (X-band). Moreover, the analysis of effective medium parameters was also included in this study. High-Frequency Simulation 15.0 and Advanced Design System 2020 software validated the transmission coefficient results. Simultaneously, the proposed multi-layered metamaterial design with Rogers RO3006 substrate material exhibited a unique transmission coefficient using double, triple, and quadruple layers. The two resonant frequencies in the unit cell design were successfully increased to three in the double-layer structure at 6.34 GHz (C-band), 8.46 and 11.13 GHz (X-band). The proposed unit cell design was arranged in an array structure to analyse the performance changes in the transmission coefficient. Overall, the proposed metamaterial design accomplished the miniaturisation concept by arranging unit cells in a multi-layer structure and possesses unique properties such as a highly effective medium ratio and left-handed characteristics.

Improvement of the Shielding Effectiveness of PMMA/MWCNTs/Ag Hybrid Composite for X-Band Application

Herein, the PMMA/MWCNT/Ag hybrid composite films are prepared by solvent casting method to be used in an electrical application. The AC conductivity and dielectric characteristics have been investigated at room temperature. The electrical conductivity of the hybrid composite reaches a percolation critical concentration of 2.14×10-4 S/cm by Ag doping. For all PMMA/MWCNT/Ag hybrid composites, the frequency-dependent dielectric constant decreases as the frequency area widens. As the concentrations of MWCNT and Ag increase, the AC conductivity exhibits an increasing trend. The MWCNT and Ag content was found to significantly affect the SE of the given composites. A high electromagnetic (EM) shielding efficiency (SE) was achieved between 8.2 and 12.4 GHz (X-band). The highest EM attenuation of 18 dB at 12 GHz was achieved using 0.5 wt% MWCNT and Ag. The thermal analysis of the formed PMMA/MWCNT/Ag hybrid composites showed that exothermic reactions with the greatest weight loss took place between 200°C and 300°C. FESEM show that PMMA/MWCNT/Ag hybrid composites had uniform dispersion of the carbon nano tube and silver particles within the PMMA matrix .

Lightweight carbon fiber hybrid film for high-efficiency electromagnetic interference shielding and electro/photo-thermal conversion applications

Enormous electromagnetic pollutions emerge with the rapid development of electronic technique, high-performance electromagnetic interference (EMI) shielding composites are greatly desired to protect human and precision instruments from electromagnetic interference. Here we fabricated a lightweight, porous carbon fiber felt/Ag/polydimethylsiloxane (CFF/Ag/PDMS) composite film via electroless plating and dip-coating method. The obtained homogenously distributed Ag nanoparticles on the surface of carbon fibers and the porous structure of CFF endow the film with excellent electrical conductivity and superior EMI shielding effectiveness (EMI SE). The maximum electrical conductivity and EMI SE value of the composite film with a thickness of 0.21 mm reach 540.9 S/cm and 105 dB at 8.2–12.4 GHz (X-band), respectively. Benefitting from the encapsulation of PDMS, the composite film exhibits outstanding corrosion resistance and oxidation resistance. Particularly, the composite film also exhibits excellent electro/photo-thermal conversion effect with outstanding heating controllability, cyclic stability, which shows great potential in 5 G communication technology and thermal management.

Ti3C2Tx MXene/polyimide composites film with excellent mechanical properties and electromagnetic interference shielding properties

With the development of electronic products to miniaturization and high frequency, high-performance flexible electromagnetic interference (EMI) shielding materials are urgently needed to deal with electromagnetic pollution. Two-dimensional transition metal carbide/polyimide (Ti3C2Tx MXene/PI) films were synthesized by in situ polymerization and a simple scratch method in this paper. The Ti3C2Tx MXene nanosheets give the films good EMI shielding effectiveness (SE) and electrical conductivity. Specifically, the film with a thickness of 0.11 mm (Ti3C2Tx content of 30 wt%) exhibits an EMI SE of 34.73 dB and a specific EMI SE (SE/thickness) of 315.73 dB/mm in the frequency range of 8.2–12.4 GHz (X-band). In addition, the films have a tensile strength of 67.58 MPa, and a high decomposition temperature of 510 ℃ in N2 atmosphere. Therefore, we believe that the prepared Ti3C2Tx/PI films with good comprehensive performance have enormous potential in the field of lightweight and flexible EMI shielding materials.

Design of a compact metamaterial absorber with wide angular stability and polarisation insensitive for C, X and broad Ku band applications

Abstract The article presents the design and development of a metamaterial-based microwave absorber having polarisation insensitivity, broad angle of incidence, low profile, and compactness in the microwave frequency range. The unit cell focuses to achieve maximum absorption at C-, X- and broad Ku-bands. The structure is simulated and the results are analysed for different angles of polarisation and angle of incidence. The dimension of the proposed structure is ultrathin and compact having an overall dimension of 8 mm × 8 mm × 0.8 mm. The dimensions are optimized in such a fashion to achieve three different peaks at three different bands thereby making the triple-band behaviour of the metamaterial absorber possible. The structure is providing absorption of 99.14% absorption at 6.08 GHz (C-Band) while absorption of 98.29% is achieved at 9.49 GHz (X-band) and 265 MHz bandwidth with above 95% absorption from 16.57 GHz to 16.83 GHz (Ku-Band) in the microwave regime. The absorber patch is a composition of square ring patches and a central square ring annexed with triangles on four sides, the split ring providing a combinational effect witnessing the desired absorption at designated frequencies. The unit cell dimension at a lower cut-off frequency is 0.162 λ lowest. The proposed structure is verified for polarisation sensitivity and has a wide angle of incidence. The structure is experimentally verified for results and is found to be in close agreement with simulated ones. The compactness of structure with the attainment of the highest form of absorption in different bands including the 265 MHz high absorption band provides the scope of applicability in various engineering applications at microwave regimes.