• Current Research on Agriculture and Life Sciences
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• 제32권3호
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• pp.131-134
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• 2014

The thermal death kinetics of the Black timber bark beetle, Xylosandrus germanus, was investigated to develop a heat treatment for control of infested wood packing materials used to export goods. To determine the feasibility of microwave irradiation as an alternative control method, laboratory experiments irradiating wooden blocks of Douglas fir ($200{\times}200{\times}250mm$), which were artificially infested with adults, with 2.45 GHz of microwave energy. All (100%) Ambrosia beetle adults were killed by both hot water treatments and microwave irradiation at $52^{\circ}C$ and $58^{\circ}C$, respectively. Probit analyses estimated the internal wood temperature required to produce Probit (0.99) efficacy to be $64.7^{\circ}C$ (95% CI $62.4-69.9^{\circ}C$) at one minute after microwave treatment.

• 한국ITS학회 논문지
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• 제7권4호
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• pp.86-96
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• 2008

본 논문에서는 광대역 평면 모노폴 안테나와 광대역 대역통과 스터브 여파기를 이용하여 2.45 GHz에서 무선전력 전송이 가능한 광대역 렉테나를 설계 및 제작하였다. 기존의 일반적인 평면형 안테나의 크기를 표면전류분포를 이용하여 방사체와 접지면의 크기를 줄일 수 있었고, 광대역 효과를 얻기 위해 확장된 접지면에 2차 고조파가 제거된 스터브 여파기를 사용한 정류회로단을 효율적으로 집적화 시킬 수 있었다. 그 결과 본 논문에서 제안한 렉테나는 부하저항이 270 Ohm에서 80% 의 RF-to-DC Power 최대 변환 효율을 보이며, $1.8{\sim}2.8$ GHz의 넓은 대역에서 RF-to-DC Power 변환효율이 50% 이상을 유지한다.

• 전자공학회논문지A
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• 제29A권2호
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• pp.18-23
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• 1992

Recently, SSPAs(Solid-State Power Amplifiers) with high linearity and efficiency replace TWTAs (Traveling-Wave-Tube Amplifiers) in satellite transponders. In this paper, a power amplifier with maximum output power is designed and constructed using GaAs FET(MGF-1302) as a test model for the development of SSPAs. For conjugate matching of input and output network, transimission lines and stubs are optimized using microwave CAD program, LINMIC+. Power amplifier is realized on the teflon substrate($\in$S1rT=2.45) with a bandwidth of 1GHz at a center frequency of 8GHz. Maximum stable gain of simulation and simulation and experimental result is obtained 9.23, 7.65 dB, respectively.

• 한국세라믹학회지
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• 제41권1호
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• pp.9-12
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• 2004

The effect of x wt% CuO-y wt% $V_2O_5$ content on the microwave properties of $(Pb_{0.45}Ca_{0.55})[(Fe_{0.5}Nb_{0.5})_{0.9}Sn_{0.1}]O_3$ (PCFNS) ceramics was investigated. In order to decrease the sintering temperature and use as a Low Temperature co-firing Ceramics (LTCC), CuO-$V_2O_5$ are added in the PCFNS. The bulk density, dielectric constant (${\varepsilon}_r$) and quality factor(Q${\cdot}f_0$) increased with increase in CuO content within a limited value. The microwave properties were degraded with increases in $V_2O_5$ content. The temperature coefficient of the resonant frequency (${\tau}_f$) of PCFNS was shifted to positive value abruptly with increasing the $V_2O_5$ content, while the ${\tau}_f$ was slightly shifted to positive value with increasing the CuO content. The optimized microwave properties, ${\varepsilon}_r$ = 88, Q${\cdot}f_0$ = 6100 (GHz), and ${\tau}_f$ = 18 ppm/$^{\circ}C$, were obtained in $(Pb_{0.45}Ca_{0.55})[(Fe_{0.5}Nb_{0.5})_{0.9}Sn_{0.1}]O_3$ with 0.2wt% CuO 0.05 wt% $V_2O_5$ and sintered at $1000^{\circ}C$ for 3 h. The relationship between the microstructure and microwave dielectric properties of ceramics was studied by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM)

• 한국재료학회지
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• 제6권6호
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• pp.576-584
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• 1996

The zirconia-alumina composite, a low loss material, was sucessfully sintered using a 2.45 GHz microwave radiation. The dense zirconia was used as a microware coupling aid. The effect of microwave power level on the heating rates of samples and the feasibility of microwave energy use in processign ceramec materials were obtained. It was also obtained how to accurately measure the temperature. According to the microwave heating theory, heating mechanisms were discussed.

• 한국산업융합학회 논문집
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• 제2권1호
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• pp.69-75
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• 1999

Intending to develop a new rubber curing process using only microwave, the both the characteristics of cure and the mechanical properties of rubbers for the tire tread, for which a green styrene-butadiene compounds had been cured with 2.45 GHz microwave, have been compared with those of the custom thermal cured rubber. The unintentional hot spot formation in the compound during the microwave curing has not found where the compound has a microwave absorbing ceramic powders in 4.18 weight percents and the supplying voltage has been adjusted to 90 volts. The new microwave process accomplished preheating to 418K in a quarter of the thermal cure time. The average tensile strength of the microwave-cured rubber indicating $190kg/cm^3$ was compatible to that of the thermal cure. In conclusion, the new microwave cure had approved to be applicable in a commercial plant.

• 전기학회논문지
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• 제62권6호
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• pp.792-797
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• 2013

In a indoor microwave power distribution system, matching-type power dividing switch is proposed and designed with a various power dividing ratio. A matching coaxial cable probe is used behind the output probe for the reflecting power absorption. Reflecting characteristics of the matching coaxial cable probe are calculated by analyzing the S-parameter of this structure. Newly proposed matching-type switch shows a very low return loss less than -30dB at the operating frequency of 2.45GHz with a dividing power ratio of 50.2%. The simulated results by use of 3-stage power divider shows a good agreement with the theoretical estimation for the various combination of the different switching ratio.

• 한국전자파학회논문지
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• 제29권6호
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• pp.424-432
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• 2018

본 논문에서는 현재 산업현장에 많이 쓰이고 있는 개방형 컨베이어 벨트형 마이크로파 건조기의 전자파 차폐 특성에 대해 분석 및 연구를 진행하였다. 특히, 범용의 2.45 GHz 마그네트론을 사용한 개방형 컨베이어 벨트형 건조기의 전자기파 누설 문제를 직사각형 도파관에 요철을 적용하여 개선하였다. 본 논문은 요철을 적용한 직사각형 도파관의 감쇠 특성을 살펴보기 위해 제안된 도파관의 구조에 따른 최적 차폐특성의 모의해석을 수행하였다. 또한, 요철 직사각형 도파관을 제작하여 IEEE Std. 299 규격에 따라 차폐특성을 검증하기 위해 제안된 요철 직사각형 도파관을 갖는 실제 마이크로파 건조기 제품에 적용하였으며, 대략 30 dB 이상의 차폐특성을 확인하였다.

• 전기학회논문지
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• 제64권3호
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• pp.422-428
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• 2015

A 2.45GHz microwave plasma source with a linear antenna has been developed for low temperature large scale deposition processing. Microwave power is transmitted through WR340 waveguide and a copper rod, linear antenna, is located in a quartz tube. The power matching is effectively achieved by a linear antenna is located at ${\lambda}_g/4$ or $3{\lambda}_g/4$ from the end of WR340 waveguide. The Ar plasma was generated along the surface of quartz tube and a clear standing wave pattern with nearly 10cm wavelength was observed at Ar pressure of 200mTorr and 200W input power. The electron density and electron temperature were investigated by using the electrostatic probe. The electron density and electron temperature were highly measured near the surface of quartz tube. Ar plasma density along the quartz tube is mostly uniform despite standing wave set-up and antenna of long length. A uniform temperature was measured at 10~40cm distance from the end quartz tube and 5cm distance from the surface of quartz tube.

• 한국전자파학회논문지
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• 제20권9호
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• pp.862-867
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• 2009

본 논문에서는 2 mW/$cm^2$ 이하의 낮은 입력 전력 밀도에서 동작하는 2.45 GHz 렉테나를 제안하였다. 제안된 렉테나는 다이오드 2개를 사용하는 배전압 구조의 정류부와 다이오드에서 발생하는 2차 하모닉의 재 방사를 억압하기 위한 인쇄형 야기 안테나 구조를 사용하여 설계하였다. 인쇄형 야기 안테나는 2.45 GHz에서 약 5 dB의 이득을 가지며, 안테나를 통해 입력된 전력이 $0{\sim}14\;dBm$일 때 렉테나의 변환 효율은 $32{\sim}42%$으로 측정되었다. 개발된 렉테나는 저전력 소자의 전원 공급에 활용될 것으로 기대된다.