• Journal of the Korean Magnetics Society
• /
• v.25 no.5
• /
• pp.149-155
• /
• 2015

The ECR (Electron Cyclotron Resonance) Ar ion milling was manufactured to fabricate the device of thin film. The ECR ion milling system applied to the device etching operated by a power of 600W, a frequency of 2.45 GHz, and a wavelength of 12.24 cm and transferred by a designed waveguide. In order to match one resonant frequency, a magnetic field of 908 G was applied to a cavity inside of ECR. The Ar gas intruded into a cavity and created the discharged ion beam. The surface of target material was etched by the ion beam having an acceleration voltage of 1000 V. The formed devices with a width of $1{\mu}m{\sim}9{\mu}m$ on the GMR-SV (Giant magnetoresistance-spin valve) multilayer after three major processes such as photo lithography, ion milling, and electrode fabrication were observed by the optical microscope.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.24 no.5
• /
• pp.508-517
• /
• 2004

We described a near-field scanning microwave microscope which uses a high-quality dielectric resonator with a tunable screw. The operating frequency is f=4.5 5GHz. The probe tip is mounted in a cylindrical resonant cavity coupled to a dielectric resonator We developed a hybrid tip combining a reduced length of the tapered part with a small apex. In order to understand the function of the probe, we fabricated three different tips using a conventional chemical etching technique and observed three different NSMM images for patterened Cr films on glass substrates. We measured the reflection coefficient of different metal thin film samples with the same thickness of 300m and compared with theoretical impedance respectly. By tuning the tunable screw coming through the top cover, we could improve sensitivity, signal-to-noise ratio, and spatial resolution to better than $1{\mu}m$. To demonstrate the ability of local microwave characterization, the surface resistance of metallic thin films has been mapped.

• Journal of the Mineralogical Society of Korea
• /
• v.29 no.2
• /
• pp.47-58
• /
• 2016

The Fe-component of pyrophyllite is an impurity that reduces its grade in the final product. In order to identify the amount of impurity in pyrophyllite and to remove the Fe from the ore using a dry method, microwave heating and magnetic separation were carried out. Pyrite and hematite were identified to contain pyrophyllite by microscopy, XRD, XRF, SEM/EDS and EPMA analysis. It is suggested that the euhedral pyrite in the pyrophyllite is formed by hydrothermal solution, and then the dissolution cavity structure is formed with a partial remainder of the pyrite which dissolved in acidic water. And the $Fe^{3+}$ ion contained in the acidic water precipitated out in the concentric structure of hematite as the origin of sedimentary structure. As a result of the microwave heating and magnetic separation experiments, the Fe removal rates obtained were 96% and 93% from pyrophyllite ore from the Sunsan mine and Wando mine, respectively. It is confirmed that the microwave heating and magnetic separation method was an environmentally friendly method to upgrade the low-grade pyrophyllite.

• Journal of the Korean Institute of Telematics and Electronics D
• /
• v.34D no.8
• /
• pp.1-7
• /
• 1997

In ahigh power amplifier design, power combiner/divider is used to connect low power amplifiers in parallel. The raidal structure of the powe combiner/divider has not only a good characteristics of port-to-port isolation but also an advantage of giving a redundancy to the structure itself by using RF switches. The parastics of a power resistor, that would be a problem in design process, are removed by both slot lines and cavity resonators, and the comon node in the circuit is rdesigned as a planar topology, and thus a new type of 4-way radial power combiner/divider is accomplished at 1840 ~ 1870 MH PCS frequency band. The insertion loss, reflection, and isolation characteristics of 40way radial power combiner/divider which can be adaptable to PCS system in this thesis are -0.3dB, -24dB,a dn -27dB respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.07b
• /
• pp.578-581
• /
• 2004

유전체가 삽입된 공동 공진기는 유전체에 대부분의 전자계가 집속되어 있기 때문에, 도체 손실이 매우 적고 높은 Q값과 온도 안정성이 뛰어나다. 동일한 주파수에서 동작하는 다른 필터에 비해 상대적으로 작기 때문에 소형화에도 적합하다. 본 논문에서는 유전체가 삽입된 공동 공진기의 전자기 분포와 특성을 수치해석과 HFSS(High Frequency Structure Simulator)를 이용하여 분석하였고 이 결과를 토대로 HFSS를 이용한 순차적 방법을 도입하여 4-pole 이중모드 대역통과 필터를 설계, 제작하였다.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.16 no.1
• /
• pp.33-39
• /
• 1979

The resonance frequency of the slot-line resonator in the shielding box is analyzed. It is verified experimentally that an X-Band oscillator may be realized by the resonator in the microstrip circuit mount as a shielding cavity, and by shunt-connecting the IMPACT diode on the slot-line, And the oscillating power can be coupled with the microstrip by the coupling aperure on the opposite surface of the microstrip by the coupling aperure on the opposite of the substrate of the microstrip cirsuit.

• 한국초전도학회:학술대회논문집
• /
• v.10
• /
• pp.21-21
• /
• 2000

The Josephson Plasma resonance in single crystalling Bi2Sr2CaCu2O8 has been investigated at a microwave frequency of 35 GHz in a cavity resonator. A sharp resonance is observed in a perpendicular oscillating magnetic field. The former is independent of the sample dimension, shile the latter shift to higher field as the sample size L is reduced, and it disappears when L becomes smaller than the critical length. The longitudinal plasma mode is a Nambu-Goldston mode in a superconductor, the experimental distinction between the longitudinal and the transverse mode leads to the conclusion that the existence of the Nambu-Goldston mod as predicted by Anderson was experimentally confirmed by direct observation of the Josephson plasma resonance with longitudinal excitations. The finite gap found in Josephson plasma resonance also provides a direct proof of the Anderson-Higgs mechanism within the context of the spontaneously broken phase symmetry of the Gauge-field theory in a superconductor.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.31A no.4
• /
• pp.84-91
• /
• 1994

A compact electron cyclotron resonance(ECR) plasma system composed of a microwave generator and a magnet coil was fabricated. A Langmuir single probe was used to investigate the plasma characteristics of the system through I-V measurements. The performance of the compact ECR plasma system was tested for the case of silicon etching reaction with $CF_{4}/O_{2}$(30%) mixed gas. Electron density and etch rate increased to maximum values and then decreased with increasing argon gas pressure, but electron temperature changed in the opposite way. The electron density and the electron temperature of argon gas plasma were 0.85${\times}~5.5{\times}10^{10}cm^{-3}$ and 4.5~6.0 eV, respectively, in the pressure range from $3{\times}10^{4}$ to 0.05Torr. The etch rate reached a maximum value at the position of 2.5cm from the bottom of plasma cavity. Etch rate uniformity was $\pm$6% across 6cm wafer. Anisotropic index was 0.75 at 1.5${\times}10^{-4}$Torr.

• Proceedings of the KIEE Conference
• /
• 1997.11a
• /
• pp.649-652
• /
• 1997

The method for the calaulation of the input impedanc of cavity with water is proposed in this paper the electric field and input impedance are calaulated for the water with high conductivity to verify this method. And the electric field and RCS (radar cross section) is calculated when the plane wave scattered by high permitivity and low conductivity material. The calculated results are compared with exact solution. Then this method is compared with the conventional method.

• Journal of the Korean Vacuum Society
• /
• v.1 no.1
• /
• pp.32-36
• /
• 1992

An ECR plasma apparatus is designed and constructed. The gradient of magnetic field in microwave cavity was adjusted to provide an ECR plasma stream by electro magnetic lenz system. Employing a yoke arround the electro magnets, the magnetic field intensity was increased by 50% with the same electric current. Characteristics of the ECR plasma discharged in the apparatus were investigated by Langmuir probe method. The variations of electron temperature and electron density along chamber axis were analysed.