Design and development of Ni0.75Zn0.25Fe2O4/MWCNT microstrip patch antenna (MPA) for ISM band spectrum applications

This research paper represents the design and development of a microstrip patch antenna (MPA) for the ISM (Industrial, Scientific and Medical) band spectrum applications. The main objective of this paper is to analyze the performance of the MPA design using new engineering materials (Ni0.75Zn0.25Fe2O4/MWCNT) synthesized through chemical vapour deposition (CVD) method by utilizing the use of waste cooking oil (WCO) as a carbon source which acts as a printed radiating patch in order to replace a copper or gold (conventional) radiating patch in previous literature. The proposed antenna is fabricated on kapton substrate with dielectric constant, εr = 3.4 and loss tangent, tan δ = 0.004. The conducting patch is Ni0.75Zn0.25Fe2O4/MWCNT and ground antenna material is copper. The results demonstrate that the antenna is capable to comprehend return loss (RL) of – 24.03 dB at frequency of 2.43 GHz with bandwidth of 1.00 GHz and voltage standing wave ratio (VSWR) of 1.14. The antenna has overall dimensions of 33.60 × 41.74 × 0.025 mm3

Influence of temperature on microstructure, structural and ferroelectricity evolution properties with nano and micrometer grain size in multiferroic HoMnO3 ceramics

The influence of temperature on microstructural, structural and ferroelectric evolution properties of multiferroic holmium manganese oxide (HoMnO3) ceramics were investigated. HoMnO3 ceramics were synthesized using a mechanochemical reaction of Ho2O3 and Mn2O3 powders in a high energy ball milling machine. The powder were sintered from 600 to 1250 °C with 50 °C increments. The results shows the microstructural, structural and ferroelectric hysteresis loop were observed to be dependent on sintering temperatures. The XRD characterization suggests an improvement of crystallinity with increasing sintering temperature. The hexagonal HoMnO3 were observed at temperature ≥1200 °C with the grain size of around 1600 nm. SEM micrographs showed larger grain size as the sintering temperature increased. The SEM results revealed a transformation of crystal structure occurs from orthorhombic to hexagonal at larger grain size regime. Polarization P—electric field E ferroelectric properties were observed to be enhanced with the increase of grain size through sintering temperature. The ferroelectric behavior was observed to change with the change of microstructure along with the structure transformation from orthorhombic to hexagonal. A complete systematic studies of the micron-nanometer grain size on microstructure-properties evolution of HoMnO3 multiferrroic ceramics is higlighted

Influence of Microstructural Effect on Microvickers Hardness Properties of SiO2-Na2O-CaO (SNC) Waste Based Glass-ceramic

There are a lot of waste materials consist of silicate based such as coal combustion ash, slag from steel production, fly ash, mud, as well as glass cullet or mixtures to produce glass-ceramics. This research work using clam shell (CS) ash and soda-lime-silica (SLS) waste glass powder for fabricating novel SiO2-Na2O-CaO (SNC) glass-ceramic. The samples were composed of SLS (50%), Na2CO3 (30%), and CS (20%) in weight percentage via conventional melt-quenching technique and solid-state sintering technique. The samples were investigated via X-Ray Diffractometer (XRD), Field emission microscope (FESEM), and microvickers hardness tester. The samples were sintered at 550-950 °C to investigate the influence of microstructural effect on microvickers hardness properties at applied force 0.5 and 1.0 kgf. The optimal Vickers hardness properties at sintering temperature 850 °C due to high crystallization of SiO2 phase from the residual glass and CaO content enhanced the viscosity flow, high compactness of particles arrangement and densification of sample

Influence of Microstructural Effect on Microvickers Hardness Propertiesof SiO2-Na2O-CaO (SNC) Waste Based Glass-ceramic

There are a lot of waste materials consist of silicate based such as coal combustion ash, slag from steel production, fly ash, mud, as well as glass cullet or mixtures to produce glass-ceramics. This research work using clam shell (CS) ash and soda-lime-silica (SLS) waste glass powder for fabricating novel SiO2-Na2O-CaO (SNC) glass-ceramic. The samples were composed of SLS (50%), Na2CO3 (30%), and CS (20%) in weight percentage via conventional melt-quenching technique and solid-state sintering technique. The samples were investigated via X-Ray Diffractometer (XRD), Field emission microscope (FESEM), and microvickers hardness tester. The samples were sintered at 550-950 °C to investigate the influence of microstructural effect on microvickers hardness properties at applied force 0.5 and 1.0 kgf. The optimal Vickers hardness properties at sintering temperature 850 °C due to high crystallization of SiO2 phase from the residual glass and CaO content enhanced the viscosity flow, high compactness of particles arrangement and densification of sample

Synthesis and characterization of magnetic and microwave absorbing properties in polycrystalline cobalt zinc ferrite (Co0.5Zn0.5Fe2O4) composite

In this research work, magnetic and microwave absorption loss and other response characteristics in cobalt zinc ferrite composite has been studied. Cobalt zinc ferrite with the composition of Co0.5Zn0.5Fe2O4 was prepared via high energy ball milling followed by sintering. Phase characteristics of the as-prepared sample by using XRD analysis shows evidently that a high crystalline ferrite has been formed with the assists of thermal energy by sintering at 1250 °C which subsequently changes the magnetic properties of the ferrite. A high magnetic permeability and losses was obtained from ferrite with zinc content. Zn substitution into cobalt ferrite has altered the cation distribution between A and B sites in spinel ferrite which contributed to higher magnetic properties. Specifically, Co0.5Zn0.5Fe2O4 provides electromagnetic wave absorption characteristics. It was found that cobalt zinc ferrite sample is highly potential for microwave absorber which showed the highest reflection loss (RL) value of − 24.5 dB at 8.6 GHz. This material can potentially minimize EMI interferences in the measured frequency range, and was therefore used as fillers in the prepared composite that is applied for microwave absorbing material

Combination of various grain sizes from nano to micron in polycrystalline holmium manganite (HoMnO3) as potential microwave absorbing application

The combinations of various grain sizes from nano to micron in polycrystalline holmium manganite (HoMnO3) as potential microwave absorber were investigated. HoMnO3 was prepared via high energy ball milling pursued by sintering process. The phase analysis confirmed that the formation of hexagonal holmium manganite, HoMnO3 along with small amount of orthorhombic holmium dimanganese pentaoxide, HoMn2O5. SEM micrographs indicated larger grain size as the sintering temperature increased. Explicitly, HoMnO3 provides an electromagnetic (EM) wave absorption characteristics and it was found that HoMnO3 sample have a potential as an efficient microwave absorber which exhibited the maximum reflection loss value of—23.4 dB at 8.5 GHz. This study advocates that by combining different grain size (nano and micron size) would contributed an enhancement value of microwave absorption

Influence of sintering temperature on the structural, electrical and microwave properties of yttrium iron garnet (YIG)

This study investigates the structural, electrical and microwave properties of yttrium iron garnet (YIG) which focuses on the parallel evolving relationship with their dependence on the sintering temperature. The iron oxide obtained from the steel waste product (mill scale) was used to synthesize YIG. The raw mill scale underwent the milling and Curie temperature separation technique to produce high purity iron oxide powder which is the main raw material in preparing and fabricating YIG through high energy ball milling (HEBM) process. Microstructural features such as amorphous phase, grain boundary, secondary phase and intergranular pores contribute significantly to the additional magnetic anisotropy and demagnetizing fields, affecting the electric and microwave properties accordingly. The increment in electrical resistivity and decrement in linewidth while the microstructure was evolving is believed to be a strong indicator of improved phase purity and compositional stoichiometry