전자파원의 위치추정에 관한 연구

최학윤 건국대학교 1997 대학원 학술논문집 Vol.44 No.-

It is simulated space position of unwanted electromagnetic wave using array antenna model in near-field. For simulation, we assumed that it is not changed according to time. If the number of electromagnetic source is small, and if the source is located at far-field, then the position searching is possible. But we conclude that the multiple source and the source in near-field can not be searched because of the ghost wave, which produce a resolution problem, In this paper, in order to shoot this problem, we make some measured signal, designed the forward-backward prediction filter, and performed the high resolution of electromagnetic source. Brug algorithm is applied to the far-field generally, so we find the forward-backward prediction filter and source distribution. This result make a λ/4 high resolution, and an ignorantly small ghost wave between electromagnetic sources, Now we get the high resolution position searching of the multiple source and of the near-field source. This study can be utilized to find the position of unwanted radiation source which influencing neighboring instruments. It can be used for an efficient EMC. And it can be used for the position searching of the expected source, too.

PCS/IMT-2000을 위한 다이폴 배열 안테나의 설계

최학윤 한국전자파학회 2002 한국전자파학회논문지 Vol.13 No.9

본 논문에서는 PCS대역(1,750 MHz ~ l,870 MHz)과 IMT-2000대역(1,885 MHz ~2,200 MHz)에서 동작하는 광대역 8소자 다이폴 배열 구형반사판 안테나를 설계하고, 실제안테나를 제작하여 복사특성을 측정하였다. 안테나설계 는 모멘트법 과 HFSS(High Frequency Structure Simulator)를 이용하여 해석하고, 해석 된 결과로부터 안테나의 구조 값을 구하였다. 설계된 안테나의 타당성을 검토하기 위하여 8소자 다이폴 배열 구형반사판 안테나를 실제 제작하고 복사특성을 측정하여 계산결과와 비교하였다. 측정결과는 PCS대역과 IMT-2000대역에서 VSWR이 1.5 이하를 만족하였고, 이득은 전 대역에서 16 dBi 이다. 따라서 본 논문에서 설계한 안테나는 PCS/IMT-2000 기지국용 안테나로 사용할 수 있을 것으로 생각된다. In this paper, the rectangular reflector antenna with 8-dipole array for PCS band (1,750 MHz ~ l,870 MHz) and IMT-2000 band(1,885 MHz ~ 2,200 MHz) is designed and the radiation characteristics are analyzed using the method of moments and HFSS(High Frequency Structure Simulator). To verify the analysis results, rectangular reflector antenna with 8-dipole array is fabricated and the calculated results are compared with the measured results. The measured results show good agreement with the calculated results. As a result of measurements, bandwidth(VSWR< 1.5) of 450 MHz is achieved at PCS and IMT-2000 band and gain is 16 dBi. The designed antenna can be used as the base station antenna for PCS/IMT-2000.

자기보정을 이용한 교류자기장 능동차폐 시스템 설계

최학윤,조정환 한국조명.전기설비학회 2023 조명·전기설비학회논문지 Vol.37 No.4

In this paper, in order to improve the shielding performance in the field of biomagnetic measurement sensitive to external noise, we designed a Dewar to install a SQUID sensor with a resolution of 100fT or less, and a 3-axis Helmholtz coil to generate canceling magnetic field against external noise. In the designed system, Dewar was installed inside the Helmholtz, and the unwanted magnetic field and the shielded magnetic field were compared and measured. As a result of the measurement, a shielding rate of 88.2% to 96.5% was obtained in the range of 0.1Hz to 120Hz. In particular, in the 0.1Hz~10Hz band, which is the main frequency nanotechnology and biomagnetism, it was possible to obtain an shielding rate that removes 95% of noise. The results are expected to be utilized in the field of active shielding.

Pager용 Sleeve안테나의 해석 및 설계

최학윤,한종석 건국대학교 1995 대학원 학술논문집 Vol.42 No.-

The purpose of this study is to design the pager antenna used base station. Nowadays as the concern of mobile communication convert particular service to personal service, customers have been increased. When considering growth trends and latent force in domestic market, the locaIi-zation of ierminals and antennas used mobile communication is urgent. The purpose of this study is to develope base station antenna having high gain, broadband, low weigh and length,for mobile pager system. By simulation and measurement, we design the antenna of base station satisfying for the bandwidth above 10MHz and low sidelobe level. The results of this study are as follows First, the development of sleeve antenna using serial feeding method and λ/4transformer method. Second, as insert polyethylene into coqper coaxial cable, we can decrease the length and weight of antenna about 30%. Finally, the result of this paper can be used for antenna analysis and design for another collinear sleeve antenna, and same type of antenna can be also used in next generation mobile communication.Also, CT-2 which have been tested in 910MHz frequency band can be manufactured the same type of collinear sleeve antenna.

저주파 자기장 차폐를 위한 자기 센서의 성능 평가 연구

최학윤,노희정 한국조명.전기설비학회 2023 조명·전기설비학회논문지 Vol.37 No.4

In this paper, a comparative analysis of performance was conducted using three different types of sensors, namely magnetoresistive sensor, a fluxgate, and a SQUID sensor, for shielding a low-frequency magnetic field. A three-axis Helmholtz coil was designed and manufactured for the purpose of sensing and canceling out the magnetic field. Additionally, Dewar was utilized to install the SQUID sensor, which operates in a superconducting state. The measurement range for the study included frequencies ranging from 0.1Hz to 10Hz, which are relevant for precision electronic equipment used in industries as well as biomagnetic field measurements. The response speed was tested for two different cases: 0.1μs and 1μs. The results of the measurements revealed that the magnetic noise levels before shielding ranged from 57nT to 120nT for each frequency. The magnetoresistive sensor achieved a shielding rate of 21.1% to 58.4%, while the flux gate sensor ranged from 51.7% to 71.7%. The SQUID sensor, on the other hand, exhibited a shielding rate between 73.3% and 96.7%. Based on these findings, it can be inferred that the experimental results presented in this paper can be applied in the design of low-frequency magnetic field shielding, depending on the specific application requirements.

대수주기 다이폴안테나로 급전되는 코너리플렉터안테나의 해석

최학윤 한국통신학회 2003 韓國通信學會論文誌 Vol.28 No.7A

주의력 결핍 및 과잉행동 장애 고위험군 대학생의 감각처리기능이 스트레스 반응에 미치는 영향

최학윤,손유진,김진경,김보겸,김하영,권순호,노진희,이지선,정은영,정희승 한국정신보건작업치료학회 2017 한국정신보건작업치료학회지 Vol.7 No.1

목적 : 본 연구는 서울, 경기, 대전, 부산, 인천, 기타 등에 거주하는 대학생 120명중 고위험군으로 해당되는 39명을 대상으로 성인 주의력 결핍장애(Attention Deficit Hyperactivity Disorder : ADHD) 감각처리기능이 스트레스 반응에 미치는 영향을 알아보고자 하였다. 연구방법 : 고위험군 성인 ADHD 연구 대상선정을 위해 한국판 Conners 성인 ADHD 평정척도(Korean version of Conners Adult ADHD Rating Scale : K-CAARS) 검사지와 청소년/성인 감각처리 프로파일((Adolescent/Adult Sensory Profile : AASP) 검사지, 스트레스반응척도(Stress Response Inventory :SRI) 검사지 도구를 사용하였다. 결과 : 감각처리기능과 스트레스 반응 점수의 남녀 평균차이분포를 살펴보면 유의한 차이를 보이지 않았다(p<.05). 감각처리기능의 각 영역별로 스트레스반응과의 상관성을 분석한 결과 감각등록에서는 상관성의 차이가 나타나지 않았고, 감각민감성에서는 공격성 (r=-.353 p<.05), 화(r=-.482, p< .01), 우울(r=-.338, p< .01)에 상관성을 보였다. 감각회피에서는 화(r=-.377, p<.05)에 상관성을 보였고, 감각추구성향에서는 공격성(r=.475, p< .01), 화(r=.564, p<. 0.1),우울(r=.344, p< .05)에 상관성을 보였다. 다중회귀분석 결과 유의수준 .05에서 독립변수인 감각추구 스트레스 반응에 19.9% 영향을 미치고 있는 것으로 나타났다. 결론 : 성인 ADHD 고위험군 증상을 가진 감각 추구 성인의 스트레스 반응이 높은 것으로 나타났다. 따라서 감각통합 치료 프로그램 개발이 필요할 것이다. Objective : The purpose of this study was to investigate the effects of Attention Deficit Hyperactivity Disorder (ADHD) sensory processing function on the stress response in 39 high risk students among 120 college students living in Seoul, Gyeonggi, Daejeon, Busan, Incheon, And to investigate its effect. Methods : Adolescent / Adult Sensory Profile (AASP) questionnaires were administered Korean Adolescent ADHD Rating Scale (K-CAARS) and Korean Adolescent ADHD Rating Scale, And Stress Response Inventory (SRI). Result : There was no statistically significant difference between male and female averages of sensory processing function and stress response score (p <.05). The analysis of the correlation between the stress response and the sensory processing function showed that there was no difference in the correlation between sensory attributes and the aggressiveness(r = -.353, p <.05), p <.01) and depression (r = -. 338, p <.01). (R = .475, p <.01), anger (r = .564, p <.05) in the sensory seeking tendency, depression (r = .344, p <.05), respectively. Multiple regression analysis showed that the significance level of .05 was influenced by the independent variable, sensory seeking stress response, by 19.9%. Conclusions : Adult ADHD with high risk symptoms showed higher stress response. Therefore, development of sensory integration therapy program will be necessary.

Back-off bigram을 이용한 대용량 연속어의 화자적응에 관한 연구

최학윤 한국통신학회 2003 韓國通信學會論文誌 Vol.28 No.9C

이동통신 기지국 안테나를 위한 급전회로 설계

최학윤 대한전자공학회 2004 電子工學會論文誌 IE (Industry electronics) Vol.41 No.02

In this paper, the feed network for PCS base station antenna was designed using ADS. To verify the design results, feed network with 8-ports was fabricated and the calculated results were compared with measured results. The measured results showed good agreement with calculated results. As results of measurements, return loss of -30dB is achieved at PCS band. The designed feed network could used as the feed network of base station antennas. 본 논문에서는 PCS대역(1,750 MHz ~ 1,870 MHz)에서 동작하는 급전회로를 ADS (Advanced Design System)를 이용하여 설계하고, 설계된 결과로부터 급전회로의 구조 값을 결정하였다. 설계된 급전회로의 타당성을 검토하기 위하여 8포트 급전회로를 실제 제작하고 반사손실을 측정하여 계산 값과 비교하였다. 측정결과 반사손실은 -30 dB 이하를 만족하였으며 본 논문에서 설계한 급전회로는 이동통신 기지국용 안테나의 급전회로로 사용할 수 있을 것으로 생각된다.

차량감지를 위한 이방성 자기저항센서 모듈의 설계

최학윤(Hak-Yun Choi),이형일(Hyeong-Il Lee) 한국조명·전기설비학회 2011 조명·전기설비학회논문지 Vol.25 No.8

This paper is about the design of 3-axis magnetic sensor module which detects parking and moving vehicle. For the sensor module, MR Sensor from Honeywell of which maximum measurement range is ±2[G] is used. It also consisted of amplifier and sensor filter and fabricated 30×50[㎜] PCB. Fabricated sensor module produced helmholtz coil of which the length is 1.2[m] of 3-axis to know the performance. It installed sensor module at the center and measured the detected magnetic field. In result, 3-axis were detected as 0.2∼0.3[mG] and the drift of the fluctuation of magnetic field was stabilized at 0.03[mG] unit. For the performance evaluation of the vehicle detection, after the entry and parking of the vehicle, variation of magnetic field was measured as 0.323∼0.695[G] which the average 0.5[G] of the earth magnetic field was the center and the range of variation was confirmed as 0.37[G]. Therefore, the designed magnetic sensor can be used as the vehicle detection sensor module.