http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Solderless Interconnection Between Microstrip Lines Through a Thick Ground Plate
Byungje Lee 한국정보과학회 1998 Journal of Electrical Engineering and Information Vol.3 No.5
Understanding of electromagnetic coupling is an important area of research in the design and development of monolithic integrated circuits(MMICs), hybrid microwave integrated circuits(MICs) and integrated antenna arrays. The Finite Difference Time Domain(FDTD) method is developed to investigate the coupling between two microstrip lines through a circular waveguide in a thick common ground plate. Measured data along with the results obtained from Spectral Domain Moment Method(SDMM) are used to verify the solution. A parametric study illustrates the coupling behavior of the structure under investigation. It is observed that the frequency tuning and wide frequency bandwidth can be achieved by choosing appropriate geometry, and this type of transition can be significantly affected by structural parameters.
NFC Antenna Design for Low-Permeability Ferromagnetic Material
Byungje Lee,Byeongkwan Kim,Harackiewicz, Frances J.,Byeonggwi Mun,Hyunwoo Lee IEEE 2014 IEEE antennas and wireless propagation letters Vol.13 No.-
<P>A novel structure of a near-field communication (NFC) antenna for a mobile handset is proposed by changing the sequence of loop winding and modifying the inner loop structure. In general, the sintered ferrite sheets with higher relative permeability (μr ≈ 200) have been used to reduce the performance deterioration of NFC antennas due to the eddy current in the battery pack of a mobile handset. However, their costs are high, and they are considerably breakable. In this letter, we effectively enhance the performance of an NFC antenna by employing the ferrite-polymer composite with lower relative permeability (μr ≈ 55). The proposed antenna improves up to 23% more reading range and up to 65% better load modulation performance.</P>
The Application of Wavelets to Measured Equation of Invariance
Byungje Lee,Youngki Cho,Jaemin Lee 한국정보과학회 1998 Journal of Electrical Engineering and Information Vol.3 No.3
The measured equation of invariance (MEI) method was introduced as a way to determine the electromagnetic fields scattered from discrete objects. Unlike more traditional numerical methods, MEI method gives local equations and sparse matrices. Therefore, the savings in storage and computing time by the MEI method over conventional methods are very substantial. In this work, Haar wavelets are applied to the measured equation of invariance (MEI) to solve two-dimensional scattering problem. We refer to "MEI method with wavelets" as "Wavelet MEI method." The proposed method leads to a significant saving in the CPU time compared to the MEI method that does not use wavelets as metrons. The results presented in this work promise that the Wavelet MEI method can give an accurate result quickly. We believe it is the first time that wavelets have been applied in conjunction with the MEI method to solve this scattering problem.
Closely Mounted Mobile Handset MIMO Antenna for LTE 13 Band Application
Byungje Lee,Harackiewicz, Frances J.,Hyunho Wi IEEE 2014 IEEE antennas and wireless propagation letters Vol.13 No.-
<P>A compact (60 × 15 × 5 mm <SUP>3</SUP>) mobile handset multiple-input-multiple-output (MIMO) antenna for LTE 13 band (746-787 MHz) applications is proposed. The antenna consists of two symmetrical planar inverted-F antennas (PIFAs) in conjunction with a T-shaped common radiator. Without using any additional coupling elements between these closely mounted antennas, both high isolation ( > 17 dB) and low envelope correlation coefficient (ECC <; 0.05 ) are achieved. The low ECC is achieved by using diagonally orthogonal radiation patterns from optimized locations of the MIMO antenna feeds and elements. Low mutual coupling achieved by using the T-shaped common radiator gives rise to the high isolation.</P>
Byungje Bae,Keera Kang,Sung Kyu Song,Chul-Woon Chung,Yongkeun Park 한국간담췌외과학회 2022 Annals of hepato-biliary-pancreatic surgery Vol.26 No.1
Backgrounds/Aims: It is challenging to assess the efficacy of partial hepatectomy (PH) as a treatment option for patients with hepatocellular carcinoma (HCC) accompanied by cirrhosis. This study aimed to determine the cure fraction of PH for HCC accompanied by cirrhosis compared to that for HCC without cirrhosis. Methods: A systematic review was performed on outcomes of previous studies that compared recurrence-free survival (RFS) after PH in patients with HCC with or without cirrhosis. A meta-analysis was conducted to obtain the cumulative hazard ratio for two patient groups: cirrhosis and non-cirrhosis. Cure fractions after PH in both groups were determined using a cure model analysis. Results: A total of 18 studies were eligible for meta-analysis and 13 studies were selected for the cure model analysis. The cumulative hazard ratio for RFS of the cirrhosis group compared to that of the non-cirrhosis group was 1.66 (95% confidence interval [CI], 1.43–1.93). Survival data of 3,512 patients in both groups were reconstructed from survival curves of original articles for cure model analysis. The probability of being statistically cured after PH for HCC was 14.1% (95% CI, 10.6%–18.1%) in the cirrhosis group lower than that (32.5%) in the non-cirrhosis group (95% CI, 28.6%–36.4%). Conclusions: The prognosis after PH for HCC accompanied by cirrhosis is inferior to that for HCC without cirrhosis. However, a cure can be expected for one-seventh of patients with HCC accompanied by cirrhosis after PH.
Characteristics of the Microstrip Antenna on a Biased Ferrite Substrate
Lee, Byungje 광운대학교 신기술연구소 1999 신기술연구소논문집 Vol.28 No.-
페라이트 기판으로 만들어진 마이크로스트립 안테나의 입력 임피던스 특성을 연구하였다. 입력 임피던스는 페라이트 기판으로부터 그린함수를 구한 다음 모멘트 방법을 사용해서 구할 수 있다. 바이어스제의 강도를 변화시키면서 마이크로스트립 안테나의 공진 주파수의 추이를 관찰하였다. 바이어스된 마이크로스트립 안테나의 레이더 단면적 에 대한 연구도 집중적으로 진행되었다. 본 논문에서 인가된 바이어스제의 방향은 페라이트 판과 수직일 경우와 평행할 경우이다. The characteristics of input impedance for a single microstrip fatch antenna on a biased ferrite substrate is studied. The input impedance is calculated by Method of Moments(MoM) where Green's function is formulated for ferrite substrate. The variation in resonant frequencies due to the changes in biasing strength is studied. The radar cross section(RCS) of a biased ferrite microstrip antenna was also an important part of this work. The biasing direction is normal(z) or in-plane(y) to the grounded ferrite substrate. The results come from the full-wave analysis by a computer simulation.