Prevalent converters for induction heating (IH) applications employ two-stage conversion for generating high-frequency magnetic field, namely, AC to DC and then DC to high-frequency AC (HFAC). This research embarks upon a direct conversion of utility AC to high frequency AC with the design of a single-phase matrix converter (SPMC) as a resonant converter using a modified switching technique for IH application. The efficacy of the proposed approach is validated through different attributes such as unity power factor, sinusoidal input current and low total harmonic distortion (THD). The developed prototype-embedded system has high pragmatic deployment potential owing to its cost effectiveness using Arduino mega 2560 and high voltage/current as well as low switching time IXRH40N120 insulated-gate bipolar transistor (IGBT). Different results of the prototype-embedded system for IH application have been verified using Matlab Simulink environment to corroborate its efficacy.

SYNOPSISThe influence of 3-aminopropyltriethoxysilane, 3-glycidyloxypropyltrimethoxysilane, and neoalkoxytri(diocty1 pyrophosphato)zirconate on thermal expansion behavior, dielectric strength, and arc resistance of mica/epoxy composites has been investigated. The addition of mica up to 30% resulted in the reduction of thermal expansion with respect to neat resin. However, the coefficient of linear thermal expansion of 30% mica treated with aminosilane was the least among the various coupling agent-coated filler/epoxy composites. Mica (30%)/ epoxy composites showed the highest dielectric strength values (26 INTRODUCTIONThermal and electrical properties are some of the important characteristics of materials. In a polymer, such properties are significantly affected when a filler is added to it. Factors like chemical and physical characteristics of the filler and the nature of interaction between the filler and the polymer also influence these properties.Thermal expansion behavior is a function of the resin, curing agent, modifiers, and the fillers present in a composite. The lowering in the coefficient of thermal expansion is desirable in minimizing the dimensional changes occurring in a polymer or a composite exposed to temperature changes during fabrication or use. A number of research papers have appeared on the thermal expansion behavior of the composites. The degree of cure of epoxy resin using DSC'-3 and mica/epoxy insulation material has been studied using thermomechanical a n a l y~i s .~ Sega15 compared the thermal expansion behavior of particulate and fiber-filled nylon 6 above and below the glass transition temperature and correlated it to the aspect ratio of the reinforcement. Shimbio et a1.6 observed that particle-particle in-* To whom correspondence should be addressed. teraction affects the shrinkage of a composite material. Feltham and CO-workers,' on the other hand, reported that the particle size of the fillers did not have any effect on thermal expansion. Aramid fiberreinforced composites have been found to have a negative thermal expansion character.' The thermal expansion of graphite/epoxy composite materials increased significantly when exposed to moisture? Reduction of internal stress in composites is important for mechanical stability, which may be achieved by lowering the linear thermal expansion coefficient of the resin, the elastic modulus of the resin, or the Tg of the resin. For example, the dispersion of rubber particles in epoxy resin lowers the elastic modulus and, consequently, low thermal stress is developed." Gupta and Brahatheeswaran" also showed significant reduction in internal stress in mica flakefilled epoxy resin as compared to neat resin. The presence of mica results in the enhancement of the modulus of the filled resin with a small change in Tg. The coefficient of linear thermal expansion also is reduced in mica/epoxy systems.The reduction of internal stress in mica/epoxy composites is of considerable interest in electrical and electronic devices. The significance of low t...

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A Triple-band Multiple-Input-Multiple-Output (MIMO) antenna for 5G mobile terminal applications is proposed in this paper. The design comprises four-port/two resonators, each having two concentric circular slot ring radiators etched on a ground plane of size 50 mm ${\times}$ 50 mm. The antenna is fed by perpendicularly arranged 50 Ω microstrip line feeds on the top layer. Decoupling techniques were used to suppress mutual coupling between the two resonators. The perpendicular arrangement of the feed lines and port reduces mutual coupling between the two ports and increases isolation. The antenna operates in multiple bands: 3.35–3.69 GHz, 24–28 GHz, and 37–40 GHz frequency range with central frequencies at 3.5 GHz, 26 GHz, and 38 GHz, respectively allocated for 5G. The antenna provides a gain of 2.7–7.8 dB and a radiation efficiency of 0.49–0.85 in the operating bands. Diversity performance is studied in terms of the Envelop Correlation Coefficient (ECC), Diversity Gain (DG), and Total Active Reflection Coefficient (TARC) were found to be less than 0.01, greater than 9.99 dB, and less than −10 dB respectively. The proposed antenna offers good S-parameters, voltage standing wave ratio (VSWR), TARC, radiation pattern, high gain, and low ECC. The antenna was fabricated and tested. The measured results and simulated results are in good agreement. It possesses sufficient potential for 5G mobile terminal and smart wearable applications.

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