• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.1
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• pp.51-58
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• 1990

NPN Si bipolar transistors with two different emitter widths are designed and fabricated. The effects of the emitter width on the small signal parameters of BJTs are measured and discussed. A new ac method for determining the current gain, the cut off frequency and the internal capacitances from the input impedance circle characteristics as a function of the varied external series resistances is presented. This method allows an accurate characterization of bipolar transistors with high current gain. The variation of the I-V curves of the emitter junction with the reverse collector junction voltages is discussed from the changes in the intsrinsic base resistances.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.28A no.9
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• pp.743-751
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• 1991

This paper presents the 1.5\ulcorner PSA bipolar device which establishes the performance improvement such as the reduction of emitter resistance and substrate junction capacitance. To achieve the above electrical characteristics, RTA process and trench isolation technology were adapted. The emitter resistance and substrate capacitance of npn transistor having 1.5$[\times}6{\mu}m^{2}$emitter area was measured with 63$\Omega$and 28fF, respectively. The minimum propagation delay time shows 121ps at 0.7mW from the measurement of 31 stage ring oscillator.

• Journal of the Korea Society of Computer and Information
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• v.5 no.4
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• pp.102-105
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• 2000

The self-aligned AICaAs/GaAs HBTs with the mesa-etched emitter showed severe degradation in current gain under stress. The cause was identified to be due to instability of the surface states on extrinsic base. In this paper the surface states were diminished by the hetero-passivation of the InGaP ledge emitter and the reliability was drastically improved. The activation energy of current gain degradation was extracted to be 1.97eV and MTTF to be 4.8$\times$108 at 14$0^{\circ}C$ which has satisfied MIL standards.

• ETRI Journal
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• v.41 no.6
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• pp.750-759
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• 2019

Presently, the extraction of hand-crafted features is still the dominant method in radar emitter recognition. To solve the complicated problems of selection and updation of empirical features, we present a novel automatic feature extraction structure based on deep learning. In particular, a convolutional neural network (CNN) is adopted to extract high-level abstract representations from the time-frequency images of emitter signals. Thus, the redundant process of designing discriminative features can be avoided. Furthermore, to address the performance degradation of a single platform, we propose the construction of an ensemble learning-based architecture for multi-platform fusion recognition. Experimental results indicate that the proposed algorithms are feasible and effective, and they outperform other typical feature extraction and fusion recognition methods in terms of accuracy. Moreover, the proposed structure could be extended to other prevalent ensemble learning alternatives.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.1
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• pp.36-40
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• 2010

In this paper, the well-known LOB-based emitter localization using linear LSE algorithm is numerically implemented and the heuristic guidelines for the parameter values to achieve 1% RMS error are presented. In the simulation, we changed the total observation durations for LOB measurements, time interval between successive LOB measurements and sensor trajectories. The effects of the time interval of LOB measurements, the time duration of the LOB measurements and the angle of flight path arc on the performance are illustrated. The dependence of the performance on the various parameters is investigated and rule-of-thumbs for the parameter values corresponding to 1% RMS error are presented for each simulation condition.

• Journal of Positioning, Navigation, and Timing
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• v.5 no.1
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• pp.37-45
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• 2016

In this paper, design and implementation issues for a network-oriented RF emitter localization system with array antenna are discussed. For hardware, the problem of array mismatch and RF/IF channel mismatch are introduced and the calibration schemes for solving those problems are also provided. For software, it is explained how to overcome the drawback of conventional MUltiple Signal Identification and Classification (MUSIC) algorithm in a point of identifying the number of received signals and problems such as Data Association Problem and Ghost Node Problem in regard to multiple emitter localization are presented with some approaches for getting around those problems. Finally, for implementation, a criterion for arranging each of sensors and a requirement for alignment of array antenna' orientation are also given.

• Journal of the Korean Institute of Telematics and Electronics
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• v.4 no.3
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• pp.28-33
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• 1967

The analysis of differential amplifier is simplified by the extention of bisection theorem. In order to reduce the thermal and porwor drifts, a self compensating circuit is employed. The optimum conditions of the self compensating circuit are: the base-emitter voltage of one transistor should be equal to the other's base-emitter voltage for basic self compensating circuit, the tempereature coefficients of base-emitter voltage of one transistor equal to the others for thermal compensation. By regarding the thermal and power drifts the experiments were performed were performed and the numerical results were consistent with the measured values.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.154-154
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• 2000

FED(Field emission display)의 FEAs(Field emitter arrays)에 형성되어 있는 micro-tip 은 tip 표면의 오염이나 진공내부의 잔류가스에 대단히 민감하다. 특히, emitter 물질의 일함수 및 겉모양 같은 기하학적 요소에 민감한 전계방출 소자의 특성상 tip 선단이 oxidation 될 경우 일함수가 증가하여 전자방출에 필요한 구동전압이 증가하고 전자 방출의 불균일성이 커지는 문제점이 발생한다. 이에 고진공의 동작 환경 및 FEAs 제작과정이나 공기의 노출에 발생하는 tip 표면의 오염물질 제거가 요구된다. 따라서 본 연구에서는 40$\times$40mm2 FEAs에 laser power, scan speed을 달리하며 laser(cw Nd-YAG, 1064nm)을 조사하였다. laser cleaning 효과를 보기 위해 laser irradiation 전, 후에 진공도 5$\times$10-7torr irradiation 후에 emitter tip의 뚜렷한 기하학적 모양의 변화를 볼 수는 없었지만, I-V 특성이 향상 되는 것을 볼 수 있었다.

• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.6
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• pp.741-746
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• 1986

A novel n-p-n bipolar transistor of which emitter is self-aligned with base contact by polyilicon is developed for using in high speed and high packing density LSI circuits. The emitter of this transistor is separated less than 0.4 \ulcorner with base contact by self-aligh technology, and the emitter feature size is less than 3x5 \ulcorner\ulcorner Because the active region of this transistor is not damaged through all the process, it has excellent electric properties. Using the n-p-n transistors by 3.0\ulcorner design rules, a NTL ring oscillator has 380 ps, a CML ring oscillator has 390ps, and a I\ulcorner ring oscillator has 5.6ns of per-gate minimum propagation delay time.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.603-608
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• 2018

Although the voltage-applied discharge method is most widely used in the semiconductor and display industries, periodic management costs are incurred because the method causes defects due to the absorption of ambient fine dust and causes emitter tip contamination due to the discharge. The emitter tip contamination problem is caused by the accumulation of fine particles in ambient air due to the corona discharge of the ionizer. Fuzzy ball generation accelerates the wear of the emitter tip and deteriorates the performance of the ionizer. Although a mechanical cleaning method using a manual brush or an automatic brush is effective for contaminant removal, it requires management of additional mechanical parts by the user. In some cases, contaminants accumulated in the emitter may be transferred to the wafer or product. In order to solve this problem, we developed an ionizer for a clean environment that can remove the pencil-type emitter tip and directly ionize the surrounding gas molecules using the tungsten wire located inside the ion tank. As a result of testing and certification by the Korea Institute of Machinery and Materials, the average concentration was $0.7572particles/ft^3$, the decay time was less than two seconds, and the ion valance was 7.6 V, which is satisfactory.