• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.4
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• pp.465-468
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• 2009

The dispersion relation and the characteristic of propagation are measured. The measurements of the dispersion relation are observed by a plunger method employed in slow plasma density by pumping microwaves on the axis are observed in plasma loaded slow wave structure. In case of small incident microwave powers the well known plasma density cavity are observed. At the axial positions of minimal radius in the waveguides, the maxima og the electron density, the plasma potential and the RF electric field are observed in cases of high-power microwaves.

• Proceedings of the KIPE Conference
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• 2002.11a
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• pp.108-111
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• 2002

For the global microwave market, high RF power or deluxe model is applying for Inverter gradually. In this study, 120V/1200W high power Inverter was proposed and verified by an optimized design of PFM-type. Especially the steady power output control was fulfilling at +/- $10\%$ input voltage variation.

• Food Science and Preservation
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• v.13 no.6
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• pp.732-739
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• 2006

This study was performed to investigate the changes in quality properties of extract from roasted Pleurotus eryngii by microwave-assisted extraction (MAE). MAE was carried out under different conditions including ethanol concentration, extraction time and microwave power. Total phenolics compound contents, electron donating ability (EDA) and nitrite-scavenging ability at pH 1.2 were high at 50% ethanol concentration. Superoxide dismutase (SOD)-like activity was high at 75% ethanol concentration. Soluble solid and total phenolics compound content decreased as extending extraction time up to 7 min. EDA decreased as increased extraction time. SOD-like activity and nitrite-scavenging ability were not significantly different. The highest soluble solid content, total phenolics compound content and EDA were obtained at 100 W extraction of microwave power. SOD-like activity was high at 25 W. But microwave power did not significantly affect the nitrite-scavenging ability.

• Journal of the Korean Institute of Telematics and Electronics
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• v.14 no.5
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• pp.7-14
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• 1977

Conventionally, a TIVT has been used for high power amplification in the microwave frequency range. However, an ultra-high-power amplifier in the 2GHz range has successfully been designed and fabricated employing high power transistors developed recently and available commercially. In the design of the amplifier, a balanced-pair configuration is adopted in order to obtain very high microwave power, and a good impedance matching is achieved by making use of microstripline techniques. For the RF power divider as well as combiner, an approach of stripline directional coupler isadopted because of its easiness in fabrication. The coupler so designed and fabricated indicates a satisfactory performance as a quadrature hybrie coupler. Measurements on the amplifier developed for an immediate commercial application also exhibit excellent overall performance characteristics RF power output, 14 watts, gain 14dB, frequency bandwidth, 160MHz, effciency 40%.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.7
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• pp.1172-1177
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• 2004

This paper describes a output power control of magnetron for microwave oven. Magnetron is used extensively in household microwave oven and industrial microwave heating devices it is operated by 3000[V]～5000[V] dc high voltage. Power supply for driving magnetron is consisted of a bridge rectifier. HB(half bridge) inverter, full wave rectifier and gate drive circuit. In proposed system. we confirm that line input power can be controlled extensively and linearly to 24.56[%] by change of duty ratio of inverter through a experiment.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.7
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• pp.744-749
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• 2005

This paper describes the performance improvement of power control system of magnetron (MGT) for microwave oven. The MGT is used extensively in household microwave oven and industrial microwave heating devices, and is operated by 3.0[kV] $\∼$5.0[kV] dc high voltage. The proposed power supply is consisted of a bridge rectifier, step-up converter(SUC) and its controller, half bridge inverter(HBI) and its controller, and full wave double voltage rectifier(DVR). In the proposed system, a good power factor can be obtained by the SUC' switching method that the inductor current waveforms follows that of the rectified voltage, and a line input power can be controlled to a range of 17.5[$\%$] by duty ratio (DR) adjustment of the HBI.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.481-481
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• 2007

The characteristics of slow wave structure employed for backward wave oscillator expected to be a high power microwave source are studied analytically. The slow wave structure is a sinusodially corrugated wall waveguide. The waveguide is designed and transmitted characteristics for microwave are measured in the air. There exist literatures on high efficiency of enhansed radiation from backward wave oscillators involving plasmastudied experimentally another results.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.7
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• pp.1282-1287
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• 2007

We investigated the damage of the CMOS IC which manufactured three different technologies by high power microwave. The tests separated the two methods in accordance with the types of the CMOS IC located inner waveguide. The only CMOS IC which was located inner waveguide was occurred breakdown below the max electric field (23.94kV/m) without destruction but the CMOS IC which was connected IC to line organically was located inner waveguide and it was occurred breakdown and destruction below the max electric field. Also destructed CMOS IC was removed their surface and a chip condition was analyzed by SEM. The SEM analysis of the damaged devices showed onchuipwire and bondwire destruction like melting due to thermal effect. The tested results are applied to the fundamental data which interprets the combination mechanism of the semiconductors from artificial electromagnetic wave environment and are applied to the data which understand electromagnetic wave effects of electronic equipments.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.15 no.1
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• pp.10-15
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• 2005

Effects of CH₄/H₂ flow rate ratio, chuck bias and microwave power on the structural properties and particle densities of diamond thin films deposited on Ti substrates in microwave plasma CVD were examined. High quality diamond thin films were deposited on Ti substrates in 2∼3 CH₄ Vol.% conditions due to the preferential formation of sp³-bonus ana selective removal of sp²-bonus in the CH₄/H₂ mixtures, and the mechanism for the formation of diamond particles on Ti was analysed. Diamond particle density increased with increasing negative chuck bias to Ti substrate due to bias-enhanced nucleation of diamond and the threshold voltage was found at ∼-50 V. With increasing microwave power the evolution from micro-crystalline graphite layer to diamond layer was observed.

• Korean Journal of Agricultural Science
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• v.45 no.4
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• pp.847-857
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• 2018

Recently, customers' demand and attention to dried agricultural products or foods have increased due to their convenience and nutritional values. Conventional drying methods such as solar drying and hot air drying have been most widely used for producing a large amount of dried agricultural products; however, those methods require quite a long time and high energy consumption. To compensate for these issues associated with conventional methods, dielectric heating such as microwave and radio frequency heating has been used as a supplemental method in the drying procedure. This study investigated the microwave drying characteristics of squash slices with different thicknesses under different microwave power intensities and determined the best drying model that could precisely describe the experimental drying curves of the squash slices. The squash was cut into slices with two different thicknesses (5 and 10 mm), and then, they were dried under different microwave power intensity ranges between 90 and 900 W with an increase interval of 90 W. Six drying models were tested to evaluate the fit to the experimental drying data, and the effective moisture diffusivity ($D_{eff}$) values of the squash slices under microwave drying were determined. The results clearly show that as the microwave power was increased, the drying time of both squash slices was significantly decreased, and the slope of the drying rate increased. The effective moisture diffusivity was also significantly related with the microwave power intensities and thicknesses of the slices. In addition, the Page model was most suitable to delineate the drying curves of both squash slices under different microwave power intensities.