• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.11
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• pp.1098-1103
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• 2013

A low-noise amplifier(LNA) using series RLC matching network and resistive feedback at 8 GHz is presented. Inductive degeneration is used for the input matching with which the proposed LNA shows quite a wide bandwidth in terms of $S_{21}$. An equivalent circuit model is deduced for input matching by conversion from parallel circuit to series resonant circuit. By exploiting the resistive feedback and series RLC input matching, fully integrated LNA achieves maximum $S_{21}$ of 8.5 dB(peak to -3 dB bandwidth is about 3.5 GHz) noise figure of 5.9 dB, and IIP3 of 1.6 dBm while consuming 7 mA from 1.2 V supply.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.3175-3177
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• 2000

전압원과 전류원 및 RLC 수동소자들로 구성된 대형회로망에서 망(網)과 마디를 복합시킨 새로운 회로망 해석법을 제시하였다. 종래의 수식적 유도 과정이 불필요하며 도식적 추출에 의해 대형회로망을 간단히 해석한다 각 전원은 직렬 또는 병렬 임피던스를 반드시 수반하고 있지 않아도 무방하다. 망 설정과 마디 선정 과정에서의 전원 처리에 의해 회로망의 도형화 시켰고, 그로부터 행렬 형태의 부분 식을 도출하였다. 망해석법에 의한 방식과 마디해석법에 의한 기법이 가지전류방향 행렬에 의해 합성된다. 합성된 최종 식은 컴퓨터 몫이다.

• Journal of Aerospace System Engineering
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• v.15 no.5
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• pp.1-7
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• 2021

Demand for Ti-6Al-4V alloy is increasing in various industries because of its superior strength to weight and high-temperature strength properties. However, due to its low formability at room temperature, it is formed at high temperature, where its productivity and efficiency are low. The current high-temperature forming method has many limitations because it involves heating the specimen by heating the lower mold. It is expected that a process using high frequency induction heating, which can locally heat the product, can improve its productivity. In addition, time and cost can be saved if the process is simulated in advance with a reliable analysis. In this paper, we verified the reliability of the analysis by comparing the result of heating the specimen to 850 ℃ by high frequency induction heating and the temperature obtained through the co-simulation analysis.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.3
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• pp.311-316
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• 2015

This paper presents a design method for thin but wideband absorbers using resistive sheets. Its equivalent circuit consists of a series RLC resonant circuit and a short-terminated transmission line. Based on this equivalent circuit, we presented the three conditions for an electromagnetic absorber which has a thickness less than a quarter wavelength and wide absorption bandwidth at center frequency. By using an root-finding algorithm, the equivalent resistance, capacitance, and inductance of the absorbers are obtained. These equivalent circuit values for the absorber surface can be realized by a 2D periodic cross-shaped structure which has required surface resistance. Using the design method, we have designed the absorber which has 18.75 mm($67.5^{\circ}$ electrical length) thickness and 90 % absorption bandwidth of 116 % bandwidth at 3 GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.4 s.107
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• pp.317-323
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• 2006

The conventional Wheeler cap method can extract the reliable efficiency of the antenna when the antenna operates as a simple series or parallel RLC circuit model. This method, however, may give an unreliable efficiency when the antenna under test has a complicated operating principle. In this paper, we revisit the conventional Wheeler cap method and propose a modified Wheeler cap method basedon the high-order circuit model. The proposed method can provide an accurate efficiency even for the antenna with a more complicated operating principle. Then we calculate efficiencies of other antennas with different operating principles and compare the results with the simulations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.2
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• pp.324-332
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• 2007

In this paper, we developed remote control devices that can be controlled passive component e.g. resistor, inductor, capacitor that is a basic element in the electric circuit. We embodied a remote laboratory for basic circuit theory which learners can experiment controlling element value to remote through the internet. It was seen that is useful applying passive component developing to a remote laboratory. Because developed passive components can response in an experiment altering several element values to remote, they will be used very usefully in a remote experiment that equip various experiment theme. Therefor the proposed laboratory will be solved problems of virtual laboratory which students do not handle instruments in engineering experiment. With our proposed system, students can experiment any time, anywhere.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.9
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• pp.62-66
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• 2016

This paper presents a MedRadio-band low power low noise amplifier for Medical Devices. A proposed MedRadio-band low power low noise amplifier adopts a current-reuse resistive feedback topology to increase overall gm and reduce power consumption. The gain of the LNA increases by the Q-factor of the additional series RLC input matching network, and its noise figure is minimized by the similar factor. Furthermore, it consumes low power because of low supply voltage and current reuse technique. By exploiting the $g_m$-booting and matching network property, the proposed MedRadio-band low noise amplifier achieves a noise figure of 0.85 dB, a voltage gain of 30 dB, and IIP3 of -7.9 dBm while consuming 0.18 mA from a 1 V supply voltage in $0.13{\mu}m$ CMOS technology.