• Journal of the Korean Institute of Telematics and Electronics
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• v.17 no.4
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• pp.45-52
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• 1980

In order to eliminate the phase errors caused by the finite GB product of operational amplifiers, novel integnator circuits are proposed. These circuits are characterized by their positive phase error angles and integrator selectivity. The positive sign of the Q and of the circuits compensates the negative selectivity and phase error angles, inherent in the integrated operational amplifiers. Miller inverting intergrator of a biquad circuit realized by Thomas is replaced by the proposed circuit and the band-pass frequency response of the modified biquad network is experimentally analyzed. A considerable improvement is recognized to such extent that the center frequency of the band-pass filter is allowed to be shifted up to 20KHz, which has been infeasible with conventional biquad networks.

• ETRI Journal
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• v.36 no.3
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• pp.510-513
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• 2014

A Q-band pHEMT image-rejection low-noise amplifier (IR-LNA) is presented using inter-stage tunable resonators. The inter-stage L-C resonators can maximize an image rejection by functioning as inter-stage matching circuits at an operating frequency ($F_{OP}$) and short circuits at an image frequency ($F_{IM}$). In addition, it also brings more wideband image rejection than conventional notch filters. Moreover, tunable varactors in L-C resonators not only compensate for the mismatch of an image frequency induced by the process variation or model error but can also change the image frequency according to a required RF frequency. The implemented pHEMT IR-LNA shows 54.3 dB maximum image rejection ratio (IRR). By changing the varactor bias, the image frequency shifts from 27 GHz to 37 GHz with over 40 dB IRR, a 19.1 dB to 17.6 dB peak gain, and 3.2 dB to 4.3 dB noise figure. To the best of the authors' knowledge, it shows the highest IRR and $F_{IM}/F_{OP}$ of the reported millimeter/quasi-millimeter wave IR-LNAs.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.6
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• pp.580-588
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• 2009

A Missile Warning Radar is an essential sensor for active protection system to detect antitank missile in all weather environments. This paper presents the design, development, and test results of L-band pulsed Doppler radar system for main battle tank. This radar system consists of 3 LRUs, which include antenna unit, transmitter and receiver unit and radar signal & data processing unit. The developed core technologies include the patch antenna, SSPA transmitter, coherent I/Q detector, DSP based Doppler FFT filter, adaptive CFAR, SIW tracking capability, and threat decision. The design performance of the developed radar system is verified through various ground fixed and moving vehicle test.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.11
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• pp.1179-1185
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• 1991

Ultrathin Reoxidized Nitrided Oxides were formed by lamp heated rapid thermal annealing in oxyzen at temperatures of $1050^{\circ}C$-$1100^{\circ}C$ for 20, 40 seconds. The electrical characteristics of ultrathin films were evaluated by leakage current breakdown voltage. TDDB. FN tunneling. Nitridation and reoxidition condition dependence of charge trapping properties. i.e.. the flat band voltage shift $({\Delta}V_{FB})$ and the increase of charge-to-breakdown $(Q_{BD})$ induced by a high field stress where studied. As the results of analysis. rapid thermal reoxidation was achieved striking improvement of dielectric integrity, the charge to breakdown was increased and flat band voltage shift was reduced.

• Journal of electromagnetic engineering and science
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• v.4 no.1
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• pp.30-36
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• 2004

We determined equivalent circuit parameters of a 1.5 cell S-band RF gun cavity from the resonant characteristics of its decoupled cavities(half cell and full cell) using the code SUPERFISH. Equivalent circuit parameters of the 1.5 cell RF gun cavity resonated in the 0-mode were obtained easily from the circuit parameters of each decoupled cavities. In order to obtain equivalent circuit parameters for the $\pi$ -mode cavity, we calculated the differences of the resonant frequencies and the equivalent resistances between the 0- and $\pi$ -modes with slight variations of the radius and thickness of the coupling iris. From those differences, we obtained R/Q value and equivalent resistance of the $\pi$ -mode, which are directly related to the equivalent circuit parameters of the coupled cavity. Using calculated R/Q value, we can express equivalent inductance, capacitance and resistances of the RF gun cavity resonated in the $\pi$ -mode, which can be useful for analyzing coupled cavities in a steady state.

• Journal of the Korean Institute of Telematics and Electronics
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• v.15 no.5
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• pp.39-45
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• 1978

This paper described on the varactor tuning Gunn oscillator for X band. Analyzed the coplanar 2 post case using the dyadic Green's function then derived the obstacle network for the incident TE10 mode. For the electronical tuning, used the tuning varactor diode which has a high speed dynamic response characteristic and high Q. Oscillation frequency, switching mode, and stable oscillation point were calculated by the computer simulation. In the expriments, switching mode was occurred at 18 mm, 32.5 mm of the short tcircuit position, respectively. The general characteristics of the varactor tuning Gunn oscillator were abruptly changed by the moving of the short circuit and the variation of the bias voltage.

• 전자공학회논문지 IE
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• v.45 no.4
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• pp.1-6
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• 2008

A fast-hopping frequency synthesizer that reduces complexity and power consumption is presented for MB-OFDM UWB applications. The proposed architecture uses 3960 MHz LC VCO, 528 MHz ring oscillator, passive mixer and LC-tuned Q-enhancement BPF to generate Band Group 1 frequencies. The adjacent channel rejection ratio is less than -40 dBc for 3432 MHz and -H dBc for 4488 MHz. A fast switching SCL-tpre MUX is used to produce the required channel output signal and it takes less than 2.2 ns for band switching. The total power consumption is 47.9 mW from a 1.8 V supply.

• Tuberculosis and Respiratory Diseases
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• v.49 no.1
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• pp.49-59
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• 2000

Backgrounds : Recent cytogenetic studies indicated that long of the long arm of chromosome 5 is a frequent event in small cell lung canær (SCLC), suggesting the presence of a tumor suppressor gene in its place. To map the precise tumor-suppressor loci on the chromosome arm for further positional cloning efforts, we tested 15 primary SCLCs. Methods : The DNAs extracted from paraffin-embedded tissue blocks with primary tumor and corresponding control tissue were investigated. Nineteen polymorphic microsatellite markers located in the long arm of chromosome 5 were used in the microsatellite analysis. Results : We found that ten (66.7%) of 15 tumors exhibited LOH in at least one of tested microsatellite markers. Two (13%) of 10 tumors exhibiting LOH lost a larger area in chromosome 5q. LOH was observed in five common deleted regions at 5q. Among those areas, LOH between 5q34-qter and 5q35.2-35.3 was most frequent (75%). LOH was also observed in more than 50% of the tumors at four other regions, between 5q14-15 and 5q23-31, 5q31.1, 5q31.3-33.3, and 5q34-35. Three of 15 tumors exhibited shifted bands in at least one of the tested microsatellite markers. Shifted bands occurred in 2.5% (7 of 285) of the loci tested. Conclusion : Our data demonstrated that at least five tumor-suppressor loci exist in the long arm of chromosome 5 and that they may play an important role in small cell lung cancer tumorigenesis.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.3
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• pp.399-405
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• 2011

In this paper, we present the design of Q-band LC VCO and injection locking buffer for 77 GHz automotive radar sensor using 130 nm RF CMOS process. To improve the phase noise characteristic of LC tank, the transmission line is used. The negative resistance by the active device cross-coupled pair of buffer is used for high output power, with or without oscillation of buffer. The measured phase noise is -102 dBc/Hz at 1 MHz offset frequency and tuning range is 34.53~35.07 GHz. The output power is higher than 4.1 dBm over entire tuning range. The fabricated chip size is $510{\times}130\;um^2$. The power consumption of LC VCO is 10.8 mW and injection locking buffer is 50.4 mW from 1.2 V supply.

• Journal of Energy Engineering
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• v.10 no.4
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• pp.379-386
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• 2001

This experimental study deals with on Nitric Oxide Formation & Reduction in Industrial Bunner. In this study, Laser-induced fluorescence (LIF) techniques have been used for quantitative measurements of Nitric Oxide. The NO A-X (0, 0) Vibrational band around 226 nm was excited using a XeCl excimer-pumped dye laser. And on-line excitation used $P_{21}+Q_1(14.5)/R_{12}+Q_2(20.5)/P_1(23.5)$ transition, for minimizing the other interferential effect. The measurements were taken NO concentration distribution in double swirling diffusion flame. In this swirl burner, NO concentration in downstream fo the flame decrease as primary/secondary air ratio increases.