運動하고 있는 誘電體圓柱에 의한 平面電磁波의 散亂

具然健 弘益大學校 1981 弘大論叢 Vol.13 No.-

The scattering of electromagnetic waves with a dielectric column which is moving uniformly in a perpendicular direction to its axis was analyzed. A homogeneous dielectric for a moving boundary, an arbitrary polarization for the incident plane wave, and ka<<1 were assumed. It was found that for E-waves, the total scattering cross sections were the functions of relative velocity and dielectric constants and scattering patterns were circles of their centers shifted to the opposite of the moving direction and of their radii to be dependent on the relative dielectric constants, and for H-waves, total scattering cross sections were varied as relative velocity and relative dielectric constant and scattering patterns of constant moving velocity were dispersed as relative dielectric constants decreased and those of constant relative dielectric constants were also dispersed as relative velocity decreased. Ⅰ. 緖 論 Ⅱ. 理 論 Ⅲ. 檢 討 Ⅳ. 結 論 The scattering of electromagnetic waves with a dielectric column which is moving uniformly in a perpendicular direction to its axis was analyzed. A homogeneous dielectric for a moving boundary, an arbitrary polarization for the incident plane wave, and ka<<1 were assumed. It was found that for E-waves, the total scattering cross sections were the functions of relative velocity and dielectric constants and scattering patterns were circles of their centers shifted to the opposite of the moving direction and of their radii to be dependent on the relative dielectric constants, and for H-waves, total scattering cross sections were varied as relative velocity and relative dielectric constant and scattering patterns of constant moving velocity were dispersed as relative dielectric constants decreased and those of constant relative dielectric constants were also dispersed as relative velocity decreased.

주파수 체배기를 이용한 13.05 GHz용 국부발진기의 설계 및 제작

具然健,李振碩 弘益大學校 科學技術硏究所 2002 科學技術硏究論文集 Vol.13 No.-

A Ku-band local oscillator is designed using a frequency multiplier. Multiplier/filter/amplifier-chain provides the moderate conversion gain at the 6th harmonics of the fundamental frequency(2.175GHz). This design will be attractive in phase lock loop(PLL), synthesizer and up/down converter applications. The techniques for HEMT modeling and circuit design were also presented in this thesis. The device parameters were provided by manufacturer's specification. The fabricated Circuits were simulated by the harmonic balance technique using ADS. Output power of the frequency multiplier, insertion loss of the filter and the gain of the 2-stage amplifier were -16.16dBm, -2.55dB, and 22.35dB, respectively.

도파관 슬롯 배열 안테나의 유전체 커버 설계 연구

具然健,崔栽源 弘益大學校 科學技術硏究所 2003 科學技術硏究論文集 Vol.14 No.-

This paper presents a waveguide slot array antenna with a radome for 37.5~38.5 GHz frequency band. At first, four different types of waveguide single-slot antennas were designed using the High Frequency Structure Simulator (HFSS): (1) slot-only, (2) slot with diaphragms, (3) slot with a radome, and (4) slot with a radome and conducting cover with aperture. Those antennas were manufactured as the designed structure using a computer controlled milling technique, and the radiation characteristics (the return loss and the antenna pattern) of single-slot antennas were measured. Then, based on the study onthe single-slot antennas, a waveguide slot 16x16 array antenna with a radome has been designed with a 20 dB Chebyshev array factors. The 16x16 slot array antenna manufactured using a computer controlled milling technique, and measured for the return loss and the antenna pattern. It was found that the in-phase 16x16 slot array antenna with a pi-type feeding system has better antenna characteristics than the alternating-phase 16x16 slot array antenna with a T-type feeding system.

마이크로파 반도체 발진기 구성에 관한 연구

구연건,이정수,강원철 한국통신학회 1986 韓國通信學會論文誌 Vol.11 No.4

주파수와 바이어스 조건에 따라 GaAs MESFET의 소신호 S파라미터들을 측정하고, 4단자 회로망 해석에 의한 고정 주파수 마이크로파 발진기의 공진회로와 부하정합회로를 CAD로 최적화 설계하였다. 마이크로스트립 기판을 써서 6GHz의 발진기를 설계 제작하여 최적화한 자료와 실험 결과가 부합됨을 확인하였다. The small-signal S-parameters of GaAs MESFET are measured in terms of frequencies and bias conditions. The resonating network and the load matching network of the fixed-frequency microwave oscillator analyzed by two-port network analysis are designed by the optimum method of CAD. The 6GHz oscillator circuit is built and tested on the microstrip substrates. Finally, it is verified that the experimenta results conformed to the optimum data by CAD.

Ka-밴드 도파관 슬롯 배열 안테나 설계와 제작

具然健,黃志煥 홍익대학교 산업기술연구소 2002 産業技術 Vol.12 No.-

This paper presents a waveguide slot 16x16 array antenna with diaphragm for 37.5~38.5 GHz frequency band. At first, the radiation characteristics of longitudinal slots on a broadside of a waveguide have been examined. Diaphragms are used to control the impedance and to minimize the return loss of the structure. A 20 dB Chebyshev array of 16 waveguide slots has been designed by optimizing the positions and sizes of the diaphragms and the slots. Then, a serial feeding system with π-junction power dividers has also designed to get a 20 dB Chebyshev power distribution. We used the HFSS for full-wave analysis and the MW Office for equivalent circuit simulations. The 16x16 slot array antenna, which was designed for a Fixed Wireless Access System at 38 GHz frequency, gives an antenna gain higher than 30 dBi. A slot array antenna was manufactured using a computer controlled milling technique, and measured for the return loss and the antenna pattern.

곡면에서의 마이크로스트립 어레이 안테나의 복사 특성에 관한 연구

구연건,이정수,고광태 한국통신학회 1989 韓國通信學會論文誌 Vol.14 No.2

圓筒形 物體의 오목면과 블록면의 表面에 密着하여 設置한 마이크로스트립 어레이 안테나의 輻射 特性에 관하여 理論的 解析을 試圖하였으며, 實驗을 통하여 檢證하였다. 單一素子 안테나의 解析은 傳送線路 모델法을 適用하였고, 어레이 안테나의 理論은 曲面 위에 2次元的으로 配列된 각각의 單一素子에 대하여 座標移動과 回轉을 考慮한 座標變換法으로 解析하여 遠距離에서의 合成 電界 强度를 數値計算으로 구하였으며, 10GHz에서 4素子 竝列 어레이 안테나 및 마이크로스트립 給電線路를 設計 製作하여 여러 가지 曲率半徑에 대하여 反射損失, 共振周波數, 輻射패턴, 半 電力 비임幅, 利得 등과 같은 諸 輻射特性을 測定하겨 理論値와 比較 考察하였다. 理論에서 豫測한 바와 같이 오목면과 블록면에서 모두 曲率半徑의 減少에 따라 輻射 패턴의 비임 폭이 더 커지는 것을 確認하였으며, 曲面에서 座標變換法으로 計算한 마이크로스트립 竝列 어레이 안테나의 合成 輻射電力 패턴이 測定値와 잘 一致하였다. 아울러 曲率半徑의 變化에 따른 周波數의 變化, 入力 임피던스 및 利得의 變化는 無視할 수 있을 程度임을 確認하였다. In this paper, an attempt has been made to analyze the theoretically and verify experimentally the effect of curvature on the radiation characteristics of microstrip array antennas mounted conformally on the concave surface and the convex surface of the cylindrical body. The analysis of single element microstrip antenna is made by using the analysis method of Transmission Line Model. The theory of array antennas is established by application of the method of transformed coordinates, in which the translation and the ratation about each single element arrayed two-demensionally on the nonplanar surface are under consideration, and it is investigated by computation of the synthetic electric field strength in the far zone. In addition, various radiation characteristics, such as return loss, resonant frequency, radiation pattern, half-power, beamwidth, gain, are measrued and compared with the theroetical values according to the variation of curvature, by designing and building 4-element array microstrip antenna operating at 10 GHz, and microstrip feed lines. As predicted in theroy, it is verified that radiation pattern of antennas mounted on the concave and the convex surfaces alike broadens as the radius of curvature decreases. And for the curved surfaces, aggrement between computed values of the total synthetic radiation power pattern by the method of transformed coordinates and measured valuse is good. Besides, it is found that resonant frequency, input impedance and gain are hardly affected by the radius of curvature.

Microstrip-Log-Periodic 안테나의 Near-Field 特性

具然健,金將起 단국대학교 1977 論文集 Vol.11 No.-

A new class of antenna using a double ridged-waveguide type microstrip to reduce the size of Logarithmically periodic dipole array (LPDA) antenna is studied on electrical characteristics. When all the linear dipole elements of a LPDA antenna are replaced by the foreshortened dipoles, the resulting structure still maintains the frequency-independent characteristics of Log-periodic structures but suffers moderate loss in gain and directivity.

진동하는 유전체면에서 전자파의 반사와 투과(TM파에 대하여)

구연건,이정수 한국통신학회 1986 韓國通信學會論文誌 Vol.11 No.6

정현적으로 진동하는 유전체 경계면에서 전자파(TM파)의 반사, 투과현상을 진동하는 임의의 순간에 등속운동이라 가정하여 Lorentz 변환을 확대적용하여 이론적으로 해석하였다. 전자파의 입사각, 운동매질의 유전율, 진동속도의 함수로써 반사, 투과특성을 수치계산 검토하였다. In the reflection and transmission of a transverse magnetic wave(TM wave) from a dielectric plane osillating sinusoidally perpendicular to ist surface, one could assume that the boundary moves with a uniform nelocity equal to the instantaneous socillating velodity. According to the extended Lorentz transform, the reflected and the transmitted field are obatained as the function of the dielectric permittivity, the oscillating velocities, and the incident angles. The above results are analyzed graphically.

振動하는 導體平面에 의한 電磁波散亂

金斗根,具然健 弘益大學校 1982 弘大論叢 Vol.14 No.2

The signal scattered from a moving target is used to be analyzed through classical FM theory to extract the Doppler results. This method can easily be applied to the motion with uniform velocity, but is not suitable when the target motion is vibrational. As a different approach, the motional properties of the target could be identified by correlating the reflected wave with the transmitted, incident wave to derive the scattered power difference from the differently vibrating objects. A simple application to the perfectly conducting infinite plane scatterer with sinusoidal oscillation is studied.

能動 Switched-Capacitor Filter에 관한 硏究

朴俊烈,具然健 弘益大學校 1981 弘大論叢 Vol.13 No.-

The Circuit of Switched capacitor integrator, which can be used as a basic block of filter design and has transfer functions independent of parasitic capacitances between any node and ground, is presented. The output characteristics when the duty cycle of trigger frequency is varied at 50%, and 25% are observed. The limitation of the sampling frequncy are defined. Ⅰ. 序 論 Ⅱ. 抵抗素子로서의 Switched-Capacitor Ⅲ. Miller積分器와 SC-積分器 Ⅳ. 實驗 및 考察 Ⅴ. 結 論 Ⅵ. 參考文獻 The Circuit of Switched capacitor integrator, which can be used as a basic block of filter design and has transfer functions independent of parasitic capacitances between any node and ground, is presented. The output characteristics when the duty cycle of trigger frequency is varied at 50%, and 25% are observed. The limitation of the sampling frequncy are defined.