스릿트 矩形導波管을 使用한 리키波 안테나

田啓石 慶熙大學校 1982 論文集 Vol.11 No.-

In this paper, the analysis of leaky-wave antenna is studied using a microwave network approach which is based on a transverse resonance method. And then, the network resonance equations, which must be solved for the complex propagation constant of leaky waves, can be conveniently treated by a perturbation technique. In experiment a power-ratio method is used for the attenuation constant measurements of leaky waves, and a interferometer method for its guide wavelength measurements. Experimental results on leaky-wave antenna show good agreements with the theoretical characteristics.

S.C.R을 이용한 D.C전압 조정기

전기석,홍의석 光云大學校 1976 論文集 Vol.5 No.-

In the design of low cost television receivers when a well-regulated D.C. supply is desired, the Cost of the power supply becomes a major expense. This is especially true when D.C Voltages desired are around 100 Volts and Current require ments exceed 5 amperes. An inexpensive line connected system is described blow which uses an S.C.R. in series with the 120 Volts, 60Hz A.C. line. This system is ideally suited to provide about 50 to 120 Volts D.C. at Currents up to about 0.75 amps. This supply will provide high performance at low cost. Its gain and stability can be tailored to the specific application. All the solid-state components are enough to fit on a small module. It can be an inexpensive, efficient power supply system.

EG-모드 마이크로스트립 아이소레이터에 관한 연구

田啓石,丁寬秀,金容平 慶熙大學校 1980 論文集 Vol.10 No.-

In X-band, a edge-guided(EG) mode microstrip isolator is designed in which nonreciprocal attenuation is due to the ferromagnetic resonance absorption caused by a strong d-e magnetic field applied locally at the shorted edge of a ferrite microstrip. From modal analysis. the dominant EG mode has been shown to propagate alone the microstrip with one edge shorted to the ground plane. Dispersion relations and rf electric field distributions have been calculated numerically. And the upper limit and the cutoff frequency of band width have been discussed with several design parameters. A practical EG-mode microstrip isolator based on these results has been successfully designed, which has more than 25dB isolation.

초음파현미경을 이용한 micro-electronic소자의 결함 검출

田啓石 慶熙大學校 1990 論文集 Vol.19 No.-

In this paper, ultrasonic microscope system has been constructed with a immersion focused transducer and the technique to examine micro-electronic device has been analyzed. The system has been designed at the center frequency of 50 MHz. It has been shown that the resolution of system has been in the range of one wavelength and the penetration depth determined by transmission coefficient and a type of acoustic lens. The propagation charateristic of ultrasonic wave visualizing the interior of micro-electronic devices has been discussed and the experiment made in the various samlmpe(PCB, IC, power TR, a ceramic material). In experimental results, it has been shown that a small aperture type microscope has more advantages than a large aperture type in examining thick samples, and also it has been powerful tool in examing the multi-layer media and the mirco-electronic devices.

초광대역 구형패치 급전 슬롯 안테나의 설계

심인석,전계석 경희대학교 레이저공학연구소 2004 레이저공학 Vol.15 No.-

In this paper, the wide-band square patch slot antenna is designed with the low impedance feeding structure. Important parameters in the design are square patch length, width, position, and feed point position. From these parameters optimized, a square patch antenna is fabricated and measured. The measured results of the antenna are obtained following results The resonant frequency of the Fabrication square patch slot antena is 5.566GHz, bandwidth for approximately 109.314%(≤- 10 dB). It is easy to use the UWB communication.

반응성 스퍼터링에 의한 전극 및 산화박막에 관한연구

김봉열,전계석,유상록 연세대학교 산업기술연구소 1980 논문집 Vol.12 No.2

Thin films of AI and ITO were prepared by RF diode sputtering and also the thin films of AIN were deposited by rf reactive sputtering. And then, the deposition rate, electrical resistivity and spectral transmission of these flms were investigated. It is obvious from the results that the sputtering input rf power strongly influenc es deposition rate of AI and ITO thin films. On the average characteristics of ITO thin films, the electrical resistivity was 4∼6×10­⁴Ω-cm and spectral transmission was more than 80%. When the partial pressure of nitrogen in argon nitrogen mixtures was increased, the deposition rate of AIN films began to decrease drastically at nitrogen partial pressure 2∼3×10­³ Torr, presumably the electrical resistivity of films began to increase rapidly, at the same critical pressure of nitrogen.

Self-injection locking 방식을 이용한 2.4GHz ISM대역 수신기의 국부 발진기용 VCO 설계 및 제작

정원재,전계석 경희대학교 레이저공학연구소 2004 레이저공학 Vol.15 No.-

This paper suggests that the jitter of the VCO is reduced to improve the phase noise using a microstrip meander line structure. Also the phase noise is improved by using a self-injection locking method which the output signal of the VCO is feedback. A phase noise is an important factor to decide a sensitivity and selectivity of an entire system. The phase noise of the VCO using a self-injection locking method is -85.19dBc/Hz at the l0kHz offset from 1.08GHz carrier with 2V tuning voltage and -98.62dBc/Hz at the l0kHz offset from 1.18GHz carrier with 8V tuning voltage.

초음파 SPECTROSCOPY를 이용한 비파괴검사 기술

高大植,田啓石 慶熙大學校 1989 論文集 Vol.18 No.-

In this paper, construction of the ultrasonic spectroscope system and its principle of operation have been studied, and nondestructive evaluation technique using it has been analyzed. A geometrical scattering theory has been used for the theoretical analysis of flaw charaterization (orientation, shape, size), and the shape of ultrasonic spectrum by variation of flaw characterization has been simulated with various samples. In simulation results, it has been shown that the shapes of spectrum by variation of the orientation and the size of flaw was displayed with noticeable difference, and that the spectrum was obtained from sphere, elliptical cavity in titanium sample was used for the measurement of quantitative characterization of practical flaws.

Indium-Tin-Oxide 박막의 전기, 광학적 성질에 관한 연구

김장권,전계석 慶熙大學校 1986 論文集 Vol.15 No.-

In this paper, ln_2O_3-SnO_2(ITO) transparent conductive films were fabricated by the of sputtering system. The effect of sputtering conditions on the electrical and optical properties of ITO films were investigated. The sputtering target was made at the rate of 10 ㏖ % of SnO_2. The deposition was carried out in argon gas. Substrate temperature was 350℃. It was shown under these sputtering conditions that the resistivity and light transmittance of ITO film were 7 Ω/㎠ and 87%, respectively. And it was observed that the films heated above 300℃ had no changes of resistivity.

초음파를 이용한 고체내의 잔류응력측정

신진섭,전계석 慶熙大學校 1991 論文集 Vol.20 No.-

In this paper, an acoustic technique for inhomogeneous residual stress in externally loaded solid with the flaw has been studied. The relative frequency change, Δf/f, of the two signal reflected from the front surface and back of specimen has been obtained by measuring transit time. The residual stress has been determined by relative frequency change. In experiment, aluminum tensile specimen with the flaw has been made and loaded by Instrone. A spherical typed acoustic transducer of center frequency 5㎒ has been used for sending a longitudinal acoustic wave into a stressed specimen. It has been shown in experimental results that the transit time has largely changed around the flaw that residual stress has been largely distributed. It has been verified that the neck of specimen has been formed around the flaw when the specimen has been continuously loaded.