Tailoring the microstructure of Mn-Zn ferrite to electronic properties

Commercial Mn-Zn ferrite powder was milled in a planetary ball mill for 30-240 minutes. Particle size distribution in the milled powders was analyzed using a laser particle size analyzer and correlated with XRD and SEM analysis of the milled powders. Green disc and torroid samples were sintered in air in the temperature interval 800 -1300oC for 2 hours. SEM/EDS, AFM/MFM analysis of the sintered samples and measurements of their electrical properties such as DC resistance up to 500 MHz enabled establishment of a correlation between the microstructure and properties in the high-frequency range

Influence of starting powder milling on magnetic properties of Mn-Zn ferrite

In this paper, the influence of additional sieving and milling of starting industrial Mn-Zn powders on magnetic properties was investigated. The starting powder was milled for 60 minutes, followed by sieving through 325 and 400 meshes. The starting and milled powders were used to fabricate toroid shaped samples sintered at 1200°C for 2 hours. Structural parameters of the fabricated samples were analysed by X-ray diffraction and scanning electron microscopy. Complex permeability, core loss density, and hysteresis were measured using the modified watt-meter method. The complex permeability and hysteresis loop were modelled with a new model proposed in the paper. The core loss density was modelled with the Steinmetz empirical equation. The experimental results and calculations show the significance of the additional milling and sieving process on magnetic properties of Mn-Zn ferrite in the frequency range 0.1-10MHz. These processes increase the relative permeability about 3 times and decrease the core loss 4 times by milling of the starting powder

Tailoring the microstructure of Mn-Zn ferrite to electronic properties

Commercial Mn-Zn ferrite powder was milled in a planetary ball mill for 30-240 minutes. Particle size distribution in the milled powders was analyzed using a laser particle size analyzer and correlated with XRD and SEM analysis of the milled powders. Green disc and torroid samples were sintered in air in the temperature interval 800 -1300oC for 2 hours. SEM/EDS, AFM/MFM analysis of the sintered samples and measurements of their electrical properties such as DC resistance up to 500 MHz enabled establishment of a correlation between the microstructure and properties in the high-frequency range

Tailoring the microstructure of Mn-Zn ferrite to electronic properties

Commercial Mn-Zn ferrite powder was milled in a planetary ball mill for 30-240 minutes. Particle size distribution in the milled powders was analyzed using a laser particle size analyzer and correlated with XRD and SEM analysis of the milled powders. Green disc and torroid samples were sintered in air in the temperature interval 800 -1300oC for 2 hours. SEM/EDS, AFM/MFM analysis of the sintered samples and measurements of their electrical properties such as DC resistance up to 500 MHz enabled establishment of a correlation between the microstructure and properties in the high-frequency range

PERFORMANCE ANALYSIS OF A FLEXIBLE POLYIMIDE BASED DEVICE FOR DISPLACEMENT SENSING

The goal of this paper is to investigate the performance of a wireless passive displacement sensor. Displacement sensor based on the heterogeneous integration process combines traditional fabrication technologies PCB (Printed Circuit Board) and LTCC (Low Temperature Co-fired Technology) with a flexible polyimide foil. The proposed sensor uses the coil as an essential part, multiple spacers and a polyimide foil as a flexible membrane with a piece of ferrite attached to it. With the displacement of the polyimide foil, the ferrite gets closer to the coil causing an increase in its inductance and a decrease of the resonant frequency of the system (coil, ferrite and antenna). Simulation results showed that sensors with equal outer dimensions but different internal structures exhibit different performances. Two prototypes of the sensor with different ferrite dimensions are designed, fabricated and characterized. Finally, their performances are compared

A Characterization of Ceramic SMD Inductors for PCB Applications

In this paper, a measurement technique, characterization and parameters extraction of SMD inductors for PCB applications are presented. These components, manufactured by Fair-Rite, are measured and characterized using a vector network analyzer E5071B and adaptation test fixture on PCB board. Since the behavior of the component depends on the environment where the component is placed, measurement results strongly depend on the choice of the PCB. Two new adaptation test fixtures in PCB technology on different board type are presented. The equivalent circuit parameters are extracted in closed form, from an accurate measurement of the board-mounted SMD inductor S-parameters. The extraction of parameters (intrinsic and extrinsic) of SMD inductor is shown

Parameters Extraction of Ferrite EMI Suppressors for PCB Applications Using Microstrip Test Fixture

The goal of this work was to investigate the behavior of a ferrite electromagnetic interference (EMI) suppressor when placed in a real surrounding. Electrical parameter measurements of the same EMI suppressor can differ for different combination of instruments and test fixtures. For that reason specially designed microstrip test fixtures are developed for the vector network analyzer (VNA) measurements. This paper describes the measurement technique, parameters extraction, and characterization of ferrite EMI suppressors for printed circuit board (PCB) applications. Two commercially available components, multilayer chip SMD inductors in a ferrite body, are measured and characterized using a VNA E5071B and developed adaptation test fixture on PCB board. These measurements describe intrinsic and extrinsic parameters of the components and their behavior. If the components are mounted on the PCB, i.e., in a real environment, then the two-port EMI suppressor model with extrinsic parameters has to be used at RF frequencies. The comparison of measured and datasheet values is further presented

RF equivalent circuit modeling of surface mounted components for PCB applications

Purpose - The appropriate selection of a testing method largely determines the accuracy of a measurement. Parasitic effects associated with test fixture demand a significant consideration in a measurement. The purpose of this paper is to introduce a measurement procedure which can be used for the characterization of surface mount devices (SMD) components, especially devoted to SMD inductors. Design/methodology/approach - The paper describes measurement technique, characterization, and extracting parameters of SMD components for printed circuit board (PCB) applications. The commercially available components (multi-layer chip SMD inductors in the ceramic body) are measured and characterized using a vector network analyzer E5071B and adaptation test fixture on PCB board. Measurement results strongly depend on the choice of the PCB; the behaviour of the component depends on the environment where the component is placed. Findings - The equivalent circuit parameters are extracted in closed form, from an accurate measurement of the board-mounted SMD inductor S-parameters, without the necessity for cumbersome optimization procedures, which normally follow the radio frequency circuit synthesis. Originality/value - It this paper, a new adaptation test fixture in PCB technology is realized. It is modeled and it has provided the extraction of parameters (intrinsic and extrinsic) of SMD inductor with great accuracy

A novel approach to modeling and simulation of NTC thick-film segmented thermistors for sensor applications

This paper describes the design, modeling, simulation, and fabrication of thick-film segmented thermistors. These thermistors were printed on alumina using negative temperature coefficient 3K3 paste, composed of nanometer powder. Their room temperature resistance was measured versus the number of segments and electrode surface value for the fixed layer thickness and electrode spacing. After that, very large thermistors were printed to serve as both the powerful self-heaters and the heat loss sensors in the thermistor volume air flow meter and anemometer. For an application in AC bridges, impedance Z(f) and insertion loss S21 [dB] of the same largest segmented thermistor were measured using network analyzer HP8752A. Impedance modeling was performed using simple equivalent electrical circuit with circuit parameters estimated by fitting procedure (traditional approach), as well as using a commercial electromagnetic simulation program microwave office (MWO, novel approach). This was followed by the modeling of electrical current distribution over a number of segments done within the MWO. The results obtained from simulations and measurements were mutually compared

Spiral Inductor Fabricated by 3D Additive Manufacturing

This paper presents spiral inductor fabricated by 3D additive manufacturing. The inductor was made with conductive epoxy silver based paste which was injected in spiral channel fabricated in polylactide (PLA) substrate (model) using additive manufacturing technology. The fabricated structure has value of effective inductance around 415 nH, maximum quality factor around 12 and outer dimension diameter 24 mm. The prototype results show good characteristics of 3D additive manufactured spiral inductor and demonstrate an innovative approach to fabricate low-cost, passive devices such as an inductor