• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.9
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• pp.1070-1076
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• 2007

In this paper, we study the characteristics of dual band microstrip antenna with the wedge-shaped radiation patch added the slot using air substrate. Wedge-shaped patch antenna with air substrate is avoided the large probe reactance associated with a thick substrate owing to the use of short probe and good impedance matching over a wide frequency range can be obtained. Slot on the antenna radiator varies the reactance component according to the employed frequency and affect the resonance freaqency of the antenna, therefore the antenna can resonate at the dual band(cellular and PCS band). The slot length and position have an effect on the bandwidth and input impedance of the antenna are optimized by simulation. From the experiment results for the fabricated antenna, -10 dB of $S_{11}$ is content with the allocated bandwidth of Cellular and PCS system and - 15 dB of cross polarization level. From the results of this paper, it has been confirmed that the proposed antenna can be used as the base station antenna fur Cellular and PCS band.

• Journal of radiological science and technology
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• v.33 no.3
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• pp.245-252
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• 2010

This study analyzed speed of sound, impedance, attenuation coefficient in accordance with acoustic characteristic standard of body soft tissue corresponding with Annex DD of IEC standard 60601-2-37(2007) which is about tissue mimicking materials (TMM) synthesized by polyurethane as a main material and new type of n-type scatter materials. This study reached the following conclusion after analyzing and evaluating image characteristic with SONOACE 9900 c PRIME (MEDESON Co.) and brightness, maximum penetration with convex probe (2.5~5.0 MHz). When n-type scatter materials are increasingly synthesised 0~8% with prepolymer as a main material and polyol mixture as a catalyst, 1. The more scatter materials are increased, the more sound speed of TMM becomes closely similar to soft tissue. 2. The more scatter materials are decreased, the more acoustic impedance becomes closely similar to soft tissue. 3. The more scatter materials are increased, the more attenuation coefficient is increased. 4. The more scatter materials are increased, the more average brightness of images is increased, but there is threshold. 5. The maximum penetration becomes closely similar to soft tissue at the 6% TMM as a scatter material.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.223-228
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• 2007

In this paper, Wideband antenna using E-shaped stacked patches has been designed and fabricated for 4th generation mobile communication(IMT-Advanced) AccessPoint application. E-shaped patch was miniature and brodband by made the movement route of current long. And inductive of coaxial probe compensates capacitive by slot. Therefore we fabricated to improve the bandwidth of proposed antenna. The E-shaped single patch antenna has an impedance bandwidth of about 13%(510[MHz]), By adding a second patch at the top of the first patch a bandwidth of 56%(2060[MHz]). The final fabricated antenna could have a good return loss(Return loss ${\leq}-10dB$) and a high gain(over 9.6dBi) at the range of 3.23 ${\sim}$ 5.29 [GHz].

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.3 s.118
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• pp.257-264
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• 2007

In this paper, we have designed and fabricated a wide-band and high gain antenna which can integrate a standard of IEEE 802.1la$(5.15\sim5.25\;GHz,\;5.25\sim5.35\;GHz,\;5.725\sim5.825\;GHz)$. We inserted a parallel dual slot into a rectangular patch to have wide-band, and we offset an element of capacitance from the slot by using coaxial probe feeding method. We also designed a converter of $\lambda_g/4$ impedance with taper type line so that wide-band impedance can be matched easily. We finally designed structure with $2\times2$ array in order to improve the antenna gain, and the final fabricated antenna could have a good return loss(Return loss$\leq$-10 dB) and a high gain(over 13 dBi) at the range of $5.01\sim5.95\;GHz(B/W\doteqdot940\;MHz)$.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.5
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• pp.53-59
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• 2010

There are various types of antenna fed method; coaxial probe, coupling, parasitic elements, and impedance matching. In this paper, the fed method of the proposed antenna is microstrip line type. The high frequency structure simulator (HFSS) is used to analyze the characteristics of the T-shaped microstrip antenna with various patch dimensions. In comparison with the basic microstrip antenna, this proposed T-shaped microstrip antenna with 40.38 % of patch dimensions has the optimum characteristics of resonant frequency, return loss, and radiation pattern at 2.0 GHz band.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.209-209
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• 2011

플라즈마 공정에 있어 챔버 및 웨이퍼의 표면 상태변화는 공정 결과에 큰 영향을 끼치게 된다. 챔버 표면에 대한 연구는 많이 진행되어 있지만 대부분의 연구가 챔버 표면에서 일어나는 화학적 반응에 초점을 맞추고 있다. 본 연구에서는 플라즈마 상태 변화에 따른 챔버 표면물질의 전기적 특성 변화를 관찰하였다. 프로브 표면에 Al2O3로 코팅을 하고 플라즈마에 삽입 후 AC 하모닉법을 이용하여 실시간으로 표면의 축전용량을 측정하였다. 그 결과 표면의 축전용량은 플라즈마에 인가한 전력과 표면이 플라즈마에 노출된 시간에 따라 변하는 것이 관찰되었다. 플라즈마에 인가된 전력이 증가되면 처음에는 급격이 축전용량이 증가하였고, 그 후 시간이 지날수록 천천히 수렴되었다. 유전물질의 축전용량은 그 물질의 온도와 연관이 있다. 실험 결과로 미루어 보았을 때, 플라즈마에서의 표면의 축전용량의 변화는 플라즈마로부터 표면으로의 열전달에 의한 표면의 온도 변화에 의한 것으로 이해할 수 있다. 특히, 쉬스에서 가속되는 이온의 포격에 의해 표면 격자가 크게 진동하면서서 일반적인 온도 변화에 의한 축전용량의 변화보다 더 큰 변화가 일어난 것으로 추정된다. 공정에 사용되는 많은 챔버의 표면이나 전극의 표면은 유전체로 코팅되어 있다. 이 유전체의 특성이 온도에 의해 변하게 되면 챔버의 전기적인 특성이 변하게 되어 임피던스 매칭 조건에 변화를 가져온다. 그 결과 플라즈마의 특성도 바뀌게 되어 공정 결과에 영향을 미치게 된다. 그러므로 챔버 표면의 유전특성을 관찰하고 제어하는 것이 플라즈마의 특성을 유지시키는데 중요하다고 할 수 있다.

• Journal of the Korea Society of Computer and Information
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• v.27 no.1
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• pp.33-41
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• 2022

This paper describes a planar microstrip patch antenna designed on dielectric substrate. Two types of planar microstrip patch antennas are studied for the 5G wireless applications, one type is conventional microstrip structure, the other type is stacked microstrip structure fed by coaxial probe. Using electromagnetically coupling method, stacked microstrip patch antenna employing a multi-layer substrate structure was designed. The results indicate that the proposed stacked microstrip patch antenna performs well at 5G wireless service bandwith a broadband from 3.42GHz to 3.70GHz. The impedance bandwidth(VSWR≤2) is 360MHz(10.28%) from 3.42GHz to 3.78GHz. In this paper, through the designing of a stacked microstrip patch antenna, we have presented the availability for 5G wireless repeater system.