텔레매틱스용 광대역 LNA 설계 및 제작

김지윤,양두영 제주대학교 공과대학 첨단기술연구소 2005 尖端技術硏究所論文集 Vol.16 No.2

In this paper, the wideband low noise amplifier for telematics terminals is proposed. In order to stabilize the input and output VSWR and minimize the noise level over wide frequency ranges, the balanced configuration and double open-stub matching circuit are adaptive. And to obtain high gain over 30dB, two amplifiers composed of MGA-86563 PHEMT are connected in cascade. From the results, the proposed low noise amplifier has flat gain over 0.8-2.6GHz, low VSWR and minimum noise figure in the desired bandwidth. Total gain of LNA is 35dB and noise figure and VSWR are 2.5dB and 1.3, respectively.

능력별 평가예고제가 수학과 합업성취에 미치는 영향

김영두,정은실 晋州敎育大學校 科學敎育硏究所 2001 科學敎育硏究 Vol.27 No.-

The purpose of this study is to examine effects of a differentiated-previous notice system of assessment (DPNSA) on the mathematical achievement. For this purpose, the following problems are established. First, how differentiated materials of assessment are made and put to practical use, which are able to applied practically to the teaching of mathematics? Second, is there any difference in mathematical achievement between the experimental group which has carried into a DPNSA, and the control group which has not? This study was designed to use nonequivalent control group pretest- posttest design. Two fourth grade classes were selected from an elementary school in Chinju city for this study, one for an experimental group and the other for a control group. One calss has carried into a DPNSA and the other has not. In order to achieve the first purpose, analysis of a course of study and aim of mathematical subject are searched, and developing principles of materials for assessment and a standard plan of assessment are ready. In order to develop a DPNSA materials and throw them in the class repeatedly, teaching plans are organized and cooperative learning of small group and self-estimate are practiced during the class. The results obtained from the data analysis were as follows. There was a significant difference between the experimental group and the control group in mathematical achievement at the significant level of 0.1. That is, this research shows that there was an effects of a DPNSA on the mathematical achievement. The results are like theses. An experiment which has done a DPNSA showed better mathematical achievement than a control group which has not. The fact tells us that the DPNSA make pupils to enhance the mathematical power. By pro-supplying the affairs of problems to the pupils, this study helped to give the opportunity to solve the given problems easily to them. In the part of teachers, the result of assessment forced them to reconsider their teaching and to improve the method of teaching.

Ku대역용 편파변환 편파기 설계

김동현,서수덕,양두영 濟州大學校 工科大學 産業技術硏究所 1997 尖端技術硏究所論文集 Vol.8 No.2

In this paper, we present a polarizer that consists of three step rotary detents which can selectively convert linear polarization into circular polarization and vice versa. For the design of the polarizer, the transmission line theory is applied to design the waveguide mode transducer for the modes to be smoothly converted between rectangular and circular waveguide. A dielectric plate is inserted in circular waveguide for the conversion of a polarized wave with the angle of an inserted dielectric plate. Also, we simulated to obtain the optimum values of the transmission and the reflection coefficient characteristics at input and output port.

구형 유전체 공진 안테나의 설계 및 제작

김원률,이권익,양두영,김흥수 濟州大學校 情報通信硏究所 2000 情報通信硏究所論文集 Vol.3 No.-

In this paper. the rectangular dielectric resonant antenna(DRA) with the microstrip slot feed line is analyzed and fabricated. Microstrip slot feed line parameters are calculated and then the microstrip slot feed line is manufactured by FR-4. Also the rectangular DRA having a value of ε_(r) = 36 is fabricated for ISM(Industrial. Scientific, Medical) telecommunication operating in the range of 2.40GHz to 2.4835GHz. The measurement result had return loss of -44dB. It was -10dB lower than simulation's value with -33dB. Resonant frequency was measured at 2.44GHz.

광대역 전압제어발진기의 설계기법에 관한 연구

김윤영,양두영 濟州大學校 情報通信硏究所 1999 情報通信硏究所論文集 Vol.2 No.-

In this paper. Design methodology of Voltage Controlled Oscillator( VCO) using varactor diode. which furnish wideband tuning range. good tuning linearity and low phase noise at microwave frequencies. are proposed. The series double-tuned oscillator with additional microstrip line and inductor is optimized to improve the phase noise and the fast tuning speed. The design and simulation have been done by Serenade-8.0 design tool used in the extracted nonlinear model parameters. The designed wideband VCO has shown the phase noise of -9jdBciHz at lOKHz offset frequency and the tuning sensitivity of 50MHz/V from 2.3GHz to 2.8GHz.

직렬 결합형 PIN 다이오드를 이용한 WLL용 3-bit 위상천이기 설계

김윤영,양두영 濟州大學校 産業技術硏究所 1999 산업기술연구소논문집 Vol.10 No.2

In this paper, the 3-bit phase shifter using the series-coupled PIN diode to decrease the insertion loss is designed at WLL frequency bandwidth. The 30' bit and the 60˚ bit phase shifter are designed by the loaded-line type which is easy to obtain a small shift angle and the 90' bit phase shifter is designed by the reflection type obtaining a large shift angle. The 3-bit phase shifter is combined with the series connection of each bit phase shifter by the increasing arrangement of phase shift angle. From the results. the designed 3-bit phase shifter shows that the phase difference of input signal is shifted every thirty-degree intervals at output port. The average value of phase error is 0.53˚, maximum phase error is 1.18˚, and the insertion loss is 0.840dB -1.335dB at center frequency (2.315GHz).

시간영역에서의 유한차분법을 이용한 접합형 서큘레이터 해석

김동현,양두영 濟州大學校 工科大學 産業技術硏究所 1997 尖端技術硏究所論文集 Vol.8 No.2

A junction circulator consists of three transmission lines, connected through suitable matching networks to a magnetized ferrite resonator having three-fold symmetry. In this paper. a finite difference time domain(FDTD) method is applied to the electromagnetic wave analysis of circulator operating at 880㎒. This method is shown to be an efficient method for modeling complicated junction circulator components. The electromagnetic field components are calculated and discussed. We simulate the electric field distribution in inner circulator. The results of the FDTD method is compared with those of mode matching method and shown to be in good agreement.

액정의 물리화학적 특성 및 합성에 관한 연구-네마틱-스메틱 A 상전이 근처의 네마틱상에서 임계현상에 대한 광산란 실험연구

김두철,임동건,변영태 濟州大學校 基礎科學硏究所 1989 基礎科學硏究 Vol.2 No.1

Rayleigh 광산란 실험방법을 이용하여 액정 Octyloxycynobiphenyl(8OCB)의 네마틱-스메틱 A 상전이 근처의 네마틱상에서 산란된 빛의 세기를 온도의 함수로 측정하였다. 실험 데이타 분석으로부터 bend 탄성상수(K₃)에 비례하는 세로 방향 상관거리 ??가 임계지수 ??=0.64±0.02를 갖고 발산함을 알 수 있었다. 이 결과는 de Gennes의 모델에서 계산된 값인 ??=0.67과 유사함을 알 수 있었다. By utilizing the Rayleigh light scattering technique, we have measured the temperature dependence of scattered light in the nematic-smectic-A phase transition point of Octyloxycynobiphenyl(8OCB). The temperature dependence of bend elastic constant K₃is deduced from analysis of this data, and it is found that the longitudinal correlation length ?? diverges with critical exponent ??=0.64±0.02. This result is similar to de Gennes's prediction ??=0.67.

WLL 기지국용 다운 컨버터 설계

김윤영,문성익,허광삼,양두영 제주대학교 산업기술연구소 2000 尖端技術硏究所論文集 Vol.11 No.1

In this paper, A down converter to convert RF signal into IF signal is designed at the WLL base-station. It consists of low noise amplifier module and down mixer module. The low noise amplifier module is composed of three-stage and a feedback circuit is added in the first-stage low noise amplifier in order to obtain unconditional stability and good flatness. The configuration of the down mixer module is a single-ended type gate mixer. For the good isolation characteristic of each port, a bandpass filter and a lowpass filter are inserted in the input and output port. To design the down converter without the IF power amplifier, it is important to maximize conversion gain. So the down converter of this paper is designed for the purpose of obtaining a high conversion gain. From the results, the IF output power is -12.68dBm when the LO and the RF power level are 7dBm and -80dBm, respectively. Also when the LO power level is 7dBm, P1dB is -0.19dBm, and the RF input power range shows 70dB on wide operating range.

부사관 후보 대학생들의 학년과 성별 자가건강관리행태, 신체적 자기효능감 및 영양섭취상태에 관한 연구

김동두,김도연,백영호 釜山大學校 附設 體育科學硏究所 2014 體育科學硏究所 論文集 Vol.31 No.-

For the study on the type of self-care status, physical self-efficacy and nutritional status according to grade level and gender of cadet noncommissioned officer on college students(n=249). This study took a Chi-square to compare the type of self-care status according to grade level and gender of cadet NCOs students and physical self-efficacy, nutritional status data were analyzed by independent t-test, and the alpha level of p<0.5 was set for all tests of significance. The results of this study are as follows: Most of the students carry out this exercise, and regularly carried out by both health-training. The students showed irregular breakfast, and the preferred food of animal meat. Smoking rate is the male students 52.1%, female students 15.9%, 40.2% of the total smoking and drinking rate is the 81.1% of the total student showed that the drinking. The physical self-efficacy in significantly difference grade 2 male students was higher than that in grade 1 male students. Nutritional status of all students not enough even of fiber daily intake, and grade 2 male students was significantly lower than that in grade 1 students. Therefore, the desirable health care and diet to increase physical self-efficacy should improve the quality of life. 본 연구는 D대학 부사관 후보생들의 학년 및 성별 자가건강관리행태, 신체적 자기효능감 및 영양섭취상태를 비교 분석 하였다. 자가건강관리행태 중 운동여부는 1학년이 83.1%, 2학년이 73.7%, 남학생은 85%, 여학생은 68.3%로 실시하는 것으로 나타났으며, 운동을 실시하는 이유는 1학년 운동자체가 좋아서 36.7%, 2학년 체력증진을 위해서 62.9%, 남·여학생 모두 체력증진을 위해서 실시하는 것으로 나타났고, 규칙적으로 실시하는 운동은 두 학년 모두 헬스를 가장 많이 하는 것으로 나타났다. 아침식사는 모두 불규칙적으로 식사를 하는 것으로 나타났고, 동물성 육류를 선호하였다. 흡연율은 남학생 52.1%, 여학생 15.9%로 전체 40.2%로 나타났고, 음주율은 전체 학생의 81.1%가 음주를 하는 것으로 나타났다. 신체적 자기효능감은 남학생의 경우 2학년이 1학년보다 유의하게 높게 나타났다. 영양섭취상태는 남, 여학생 모두 섬유질 섭취량이 1일 충분섭취량에 못 미치는 것으로 나타났으며, 특히 2학년 남학생이 1학년 남학생보다 유의하게 낮게(p<.05) 나타났다. 이상의 결과 바람직한 자가건강관리행태와 식습관을 통해 신체적 자기효능감을 높이고 삶의 질을 향상 시켜야 할 것이다.