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Significant achievements in ferrite material processing enable developments of many ferrite devices with a wide range of power levels and working frequencies, which make demands for new characterization and modelling methods for ferrite materials and components. The purpose of this paper is to introduce a modelling and measurement procedure, which can be used for the characterization of two‐port ferrite components in high frequency range.

This paper presents a commercially available ferrite component (transformer) modelling and determination of its electrical parameters using in‐house developed software. The components are measured and characterized using a vector network analyzer E5071B and adaptation test fixture on PCB board. The parameters of electrical equivalent circuit of the ferrite transformer parameters are compared with values extracted out of measured scattering parameters.

A good agreement between modelled and extracted electrical parameters of the ferrite transformer is found. The modelled inductance curves have the same dependence versus frequency as extracted ones. That confirms the model validity in the wide frequency range.

In‐house developed software based on proposed model provides inclusion of the ferrite material dispersive characteristics, which dominantly determines high‐frequency behaviour of two‐port ferrite components. Developed software enables fast and accurate calculation of the ferrite transformer electrical parameters and its redesign in order to achieve the best performance for required application.

This paper aims to study the various developments taking place in the field of gas sensors made from polyaniline (PANI) nanocomposites, which leads to the development of high-performance electrical and gas sensing materials operating at room temperature.

PANI/ferrite nanocomposites exhibit good electrical properties with lower dielectric losses. There are numerous reports on PANI and ferrite nanomaterial-based gas sensors which have good sensing response, feasible to operate at room temperature, requires less power and cost-effective.

This paper provides an overview of electrical and gas sensing properties of PANI/ferrite nanocomposites having improved selectivity, long-term stability and other sensing performance of sensors at room temperature.

The main purpose of this review paper is to focus on PANI/ferrite nanocomposite-based gas sensors operating at room temperature.

The purpose of this article is to study the effect of ferrite content on electric, magnetic and microwave properties of screen-printed y(Ni0.4Co0.2Cd0.4Fe2O4) + (1 − y)Pb(Zr0.52Ti0.48)O3 (y = 0.0, 0.15, 0.30, 0.45, 1.0) thick films on alumina.

Thick films of ferrite–ferroelectric composite on alumina substrate have been delineated using screen printing technique. The structural analysis was carried out using X-ray diffraction method and scanning electron microscopy. The DC electrical resistivity was measured using the two-probe method. The magnetic measurement was carried out using a vibrating sample magnetometer. Microwave absorption was studied in the 8-18 GHz frequency range by using the vector network analyzer (N5230A). The permittivity in the 8-18 GHz frequency range was measured by using voltage standing wave ratio slotted section method.

The formation of two individual ferrite–ferroelectric phases in composite thick films was confirmed by the X-ray diffraction patterns. The scanning electron microscope morphologies show the growth of cobalt-substituted nickel cadmium ferrite grains which are well dispersed in lead zirconium titanate matrix. The DC electrical resistivity increases with increase in ferrite content and decreases with increase in temperature. The present ferrite shows ferromagnetic nature and it increases saturation magnetization and coercivity of the composite thick films. Tuning properties are observed in the Ku-band and broadband X-band microwave absorption is observed in the composite thick films. The imaginary part of permittivity increases with an increase in ferrite content, which increases microwave absorption. The real part of microwave permittivity varied from 17 to around 22 with an increase in ferrite content and it decreases with frequency. The microwave conductivity, which increases with an increase in ferrite content, reveals the loss of polaron conduction, which supports the dielectric loss in the microwave region.

Electric, magnetic and microwave properties of screen-printed y(Ni0.4Co0.2Cd0.4Fe2O4) + (1 − y)Pb(Zr0.52Ti0.48)O3 (y = 0.0, 0.15, 0.30, 0.45, 1.0) composite thick films on alumina substrate is reported for the first time.

The purpose of this paper is to investigate the effect of Mg²⁺substitution on the magnetic and electrical properties of Li_0.35−x Mg_2x Zn_0.3 Fe_2.35−xO₄ thick films synthesized with polyvinyl alcohol (PVA) matrix.

The nanoferrites Li_0.35−x Mg_2x Zn_0.3 Fe_2.35−xO₄ (x=0, 0.07, 0.14, 0.21, 0.28 and 0.35) were synthesized by chemical technique using aqueous solution of PVA (the matrix) and thick films were fabricated by screen printing technique. The DC magnetic hysteresis measurements, AC magnetic susceptibility and DC electrical resistivity were measured as a function of temperature.

The lattice parameter of thick film Li_0.35−x Mg_2x Zn_0.3 Fe_2.35−xO₄ (x=0, 0.07, 0.14, 0.21, 0.28 and 0.35) increases with the substitution of Mg²⁺ions for Li¹⁺and Fe³⁺. The surface morphology of the thick films showed the grain size increasing with Mg²⁺substitution till x=0.21 and then decreasing for the higher concentrations of magnesium. The magnetic moment n_B (μ_B) computed from the M_s obtained by extrapolation of the magnetization curve showed a gradual decrease with the composition till x=0.21, beyond which a sudden decrease was observed. The resistivity of the films at room temperature had variation with composition x, similar to that of magnetic moment. The activation energies ΔE_F and ΔE_P were found to vary with composition x of the ferrite system.

The paper reports, for the first time, the magnetic and electrical properties of fritless Li_0.35−xMg_2xZn_0.3Fe_2.35−xO₄ thick films using PVA polymer matrix. Up to x=0.21 (Mg²⁺), grain size increases and Curie temperature decreases beyond which reverse effect takes place.

The aim of this paper is to investigate permittivity of nano structured Ni_0.7‐xCo_xZn_0.3Fe₂O₄ thick films at microwave frequencies.

Nanosized Ni_0.7‐xCo_xZn_0.3Fe₂O₄ ferrites with x=0, 0.04, 0.08 and 0.12 were prepared by sucrose precursor technique using the constituent metal nitrates. Thick films of the ferrites were fabricated on alumina substrates by screen‐printing technique. Microwave dielectric constant (ε′) and the loss factor (ε″) for the thick films were measured by VSWR slotted section method in the 8‐18 GHz range of frequencies. Microwave attenuation properties were studied using a waveguide reflectometer set up.

Both the ε′ and ε″ were found to vary with frequency and composition x. It is observed that, value of ε′ increases with increase in x, due to the increase in bulk density and reduction in porosity of the material, that resulted due to the substitution of cobalt in Ni‐Zn ferrite. The microwave transmission loss offered by the thick films was found to increase with the increase in cobalt concentration x. Within the band width of 4 GHz (from 12‐16 GHz), all the films except that with x=0.04 offered the reflection loss of less than 3 dB.

The dielectric constant of Ni_0.7‐xCo_xZn_0.3Fe₂O₄ thick films have been reported for the first time. These thick films provide scope for cost effective planar ferrite devices.

The purpose of this paper is to study thickness dependent variation in microwave properties of the Mg_xMn_(0.9−x)Al_0.1Zn_0.8Fe_1.2O₄ (x=0.8, 0.9) thick films and enhancement of power efficiency of Ag thick film EMC patch antenna.

X‐band microwave properties of the Mg_xMn_(0.9−x)Al_0.1Zn_0.8Fe_1.2O₄ (x=0.8, 0.9) thick films were measured by superstrate technique using Ag thick film EMC patch antenna as the resonant element. The complex permittivity and permeability of these thick films were also measured by this technique. The microwave response of the EMC patch, complex permeability and permittivity of Mg_0.8Mn_0.1Al_0.1Zn_0.8Fe_1.2O₄ and Mg_0.9Al_0.1Zn_0.8Fe_1.2O₄ thick films and their thickness dependency were investigated.

The XRD patterns reveal the cubic spinel crystal system was obtained for both compositions. The crystallite size obtained was 134.68 nm for Mg_0.8Mn_0.1Al_0.1Zn_0.8Fe_1.2O₄ and 155.99 nm for Mg_0.9Al_0.1Zn_0.8Fe_1.2O₄ The superstrate technique has been used successfully to evaluate the complex permittivity and permeability of the ferrite thick films in the X band. The EMC patch also show thickness and composition dependent frequency agility and enhancement of power efficiency.

The complex permeability of Mg_xMn_(0.9−x)Al_0.1Zn_0.8Fe_1.2O₄ (x=0.8, 0.9) thick films measured by superstrate technique is reported in this paper. The superstrate of Mg_xMn_(0.9−x)Al_0.1Zn_0.8Fe_1.2O₄ (x=0.8, 0.9) thick films makes the Ag thick film EMC patch antenna frequency agile and power amplification is obtained.

This is indeed the age of revolution, when timeless attitudes are changing and new ways of living being born. To most it is a bewildering complex, with uneasy forbodirtgs of the outcome. Improvement and change, there must always be—although change is not necessarily progress—but with unrest in the schools, universities and industry, one naturally questions if this is the right time for such sweeping reorganization as now seems certain to take place in local government and in the structure of the national health service. These services have so far escaped the destructive influences working havoc in other spheres. Area health boards to administer all branches of the national health service, including those which the National Health Service Act, 1946 allowed local health authorities to retain, were recommended by the Porritt Committee a number of years ago, when it reviewed the working of the service.

The aim of this paper is to investigate microwave Ku band absorbance, complex permittivity, and permeability of SrFe₁₂O₁₉ thick films by a simple and novel waveguide technique.

The glass frit free or fritless strontium hexaferrite thick films were formulated on alumina by screen printing technique from the powder synthesized by chemical co precipitation method for pH 11 adjusted during the reaction. The 13‐18 GHz frequency band microwave absorbance of the SrFe₁₂O₁₉ thick films by a simple waveguide method. The complex permittivity and permeability of strontium hexaferrite thick films was measured by voltage standing wave ratio technique.

SrFe₁₂O₁₉ thick films show high ∼80 percent absorbance in the whole 13‐18 GHz frequency band. The thickness dependant microwave properties of strontium hexaferrite thick films were observed. The real permittivity ε′ lies in between eight and 35 with the variation in thickness of the thick film SrFe₁₂O₁₉. The real microwave permeability μ′ of strontium hexaferrite thick films lies in the range 1.12‐6.41. The resonance type behavior was observed at frequency 14.3 GHz. The SrFe₁₂O₁₉ thick film of thickness 30 μm could be a wide band (∼5,000 MHz) absorber with absorbance ∼87 percent for the whole 13‐18 GHz frequency band.

The complex permeability of strontium hexaferrite thick films was measured by simple novel waveguide method. The high absorbance (∼87 percent) of thick film SrFe₁₂O₁₉ over a broad band ∼5,000 MHz will be useful in achieving RAM coatings required for 13‐18 GHz frequency band.

Present 3D electromagnetic simulators have high accuracy, but they are time and memory expensive. Because of that, fast and simple expression for impedance is also necessary for initial inductor design. In this paper new efficient method for total impedance calculation of ferrite electromagnetic interference (EMI) suppressor is given. By using an algorithm, it is possible to predict correctly all variations of electrical characteristics introduced by varying geometry parameters of EMI suppressor.

The starting point for calculation of electrical characteristics of EMI suppressor is Greenhouse theory. Greenhouse decomposed inductor into its constituent segments. Basically, all segments of conductive layer are divided into parallel filaments having small, rectangular cross sections. The self‐ and mutual‐inductance were calculated using the concept of partial inductance. Total impedance of EMI suppressor is calculated taking care of dimension of chip size, material that are used and geometry of conductive layer.

The Simulator for Planar Inductive Structures (SPIS™) simulates effects of ferrite materials and geometrical parameters of planar inductive structures. With proposed software tool, designers can predict performance parameters quickly and easily before costly prototypes are built. SPIS™ software offers substantially reduced time to market, and increases device performance. The computed impedances, given by our software tool are compared with measured data and very good agreement was found.

Applied flexible efficient methods for impedance calculation of EMI suppressor are able to significantly increase the speed design of multilayer suppressors for universal series bus, low‐voltage differential signaling and in other high‐speed digital interfaces incorporated in notebooks and personal computers, digital cameras and scanners. Also, ferrite suppressors have been successfully employed for attenuating EMI in switching power supplies, electronic ignition systems, garage door openers, etc.

The paper presents realized structures of ferrite EMI suppressors. New geometries of conductive layer are proposed. In addition, using simple model of inductor, the paper develops a CAD simulation tool SPIS™ for calculation of electrical characteristics of EMI suppressors with different geometry of conductive layer.

To prepare of fine particle size magnesium ferrite pigments by sol‐gel method.

Different magnesium ferrite pigments with stoichiometric ratios were prepared by sol‐gel and dispersion methods. The characterisation of magnesium ferrite pigments were based on X‐ray diffraction, transmission electron microscope, particle size distribution, thermal and magnetometric analyses.

The type of polymer and the starting inorganic materials (oxides or salts) have a significant effect on the properties of the magnesium ferrite pigments prepared.

The magnesium ferrite pigments, prepared and used in the work reported here were synthesised from magnesium and iron oxides, oxalates and chlorides. Urea formaldehyde resin and acrylic polymer were used as the dispersing media. Various other materials, e.g. carboxymethyl cellulose, ethoxy methyl cellulose, polyvinylalcohol and 2‐hydroxyethyl methacrylate and polyacrylamide can also be used to achieve similar effect.

The sol‐gel method provided a fine particle size and different particle shapes. Therefore, the method of preparation could be used to produce fibres, films and monoliths.

The magnesium ferrite pigments prepared could be use in numerous paints for steel protection.