Eun-Kwang Koh

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

Signal integrity enhancement of high-speed digital interconnect with discontinuous and asymmetric structures for mobile applications

IEEE International Symposium on Electromagnetic Compatibility (2013)

Tae-Wan Koo Hee‐do Kang Jeunguk Ha Eun-Kwang Koh Jong‐Gwan Yook

In this paper, signal integrity (SI) of a mobile high-definition link (MHL) system is analyzed, having the discontinuous and asymmetric structures. In the SI analysis of the MHL system, three dimensional (3D) electromagnetic (EM) solver and time domain reflectometry (TDR) method are carried out. As a result, the differential signals with the discontinuous reference plane experience the degeneration of transmission characteristic due to the impedance mismatch, rendering by discontinuities in return current path of the signals. Moreover, it is found that the SI characteristic of the differential signal could be significantly degenerated, when the asymmetric guard traces with ground vias for electromagnetic interference (EMI) reduction are located closer to the signal trace than the balanced reference plane. Therefore, SI can be guaranteed with widely open eye diagram using the symmetric and continuous reference plane for the coupled signal lines in the high-speed digital interconnect.

Reflectometry

Classification of discontinuities

SIGNAL (programming language)

Ground plane

10.1109/isemc.2013.6670503

Cite

Citations (2)

EMI reduction technique by employing a conductive connection between frames

Eun-Kwang Koh Minkyu Shim Eun-Ju Hong Jai-Yeol Lee Seung-Hun Park

In this paper, we propose an EMI (Electromagnetic Interference) reduction technique by employing a conductive connection between frames. Several cconductors were used to connect two frames, which might provide another return path of signal current loop, and reduce the DM (Differential Mode) radiation from the cable. To prove the effectiveness of the conductor connection, we investigated two cases: (1) without any conductor below cable, (2) installing three different conductors of small, medium, and large sized-conductors. The results were obtained from both measurement and full-wave simulation, and we observed that EMI decreased about 1 to 10 dB μV in the frequency range from 30MHz to 1GHZ.

Common-mode signal

Conducted electromagnetic interference

Installation

10.1145/1352793.1352870

Cite

Citations (0)

Pad shape effects on high frequency signal transfer characteristics

Electrical Design of Advanced Packaging and Systems Symposium (2008)

Ki-hoon Nam Eun-Kwang Koh Eun-Ju Hong Seung-Hun Park Jai-Yeol Lee

As one of the interconnects between board to board, pads on the boards could have considerable effects on high frequency signal transfer characteristics. In this paper, pad shape effects on the signal integrity is analyzed using add-in card model by simulation, and a test fixture designed and fabricated to test to a serial-ATA cable is used to measure the effect of pad length on high frequency signal transfer characteristics. From the simulation and measurement, it is confirmed that the pads make a considerable effects on the signal transfer characteristics, especially in high frequency range, and we need to carefully design the characteristic impedance of the pads.

SIGNAL (programming language)

Fixture

Test fixture

10.1109/edaps.2008.4736013

Cite

Citations (2)

EMI Reduction Analysis by a Conductor between Frames

The Journal of Korean Institute of Electromagnetic Engineering and Science (2008)

Eun-Kwang Koh Minkyu Shim Eun-Ju Hong Jai-Yeol Lee Seung-Hun Park

본 논문에서는 프레임들을 기계적으로 고정하고 전기적으로 접지시키기 위해 사용하는 전도체의 연결에 의한 전자파 장해의 감소에 대해서 연구하였다. 프레임과 프레임 사이의 전도체의 연결은 두 프레임 사이의 전류의 귀환 통로의 길이에 영향을 미친다. 전도체 연결의 효과를 입증하기 위해서 추가적인 전도체의 연결이 없는 경우와 케이블 하단에 세 가지의 크기가 다른 전도체를 연결해 주었을 때의 결과를 비교 분석하였다. 결과들로부터 전자파 장해가 측정 주파수 범위인 30 MHz$\sim$1 GHz에서 약 1$\sim$10 dB 감소함을 확인하였다. 네트워크 분석기를 이용하여 S 파라미터를, 또 3 m 무반향실에서의 복사성 방사를 측정하였으며, 두 파라미터 사이의 상관관계를 공진 주파수의 관점에서 확인하였다. 또한, 복사성 방사의 측정과 시뮬레이션 결과를 비교하였다. In this paper, we investigated EMI(electromagnetic interference) reduction by conductor connection, which was used for fixing and electrical grounding between frames. Conductor connects two frames and then it provides the decrease of return path of signal current. To prove the effect of conductor, we measured/simulated the RE(radiated emission) with/without conductors between the two frames. From the measured/simulated results, we observed that EMI decreased about 1$\sim$10 dB at the frequency range of 30 MHz to 1 GHz. VNA(vector network analyzer) was used to measure the S parameters and the RE was measured in a 3 m anechoic chamber. The simulated and measured results are compared and discussed.

Anechoic chamber

Conducted electromagnetic interference

SIGNAL (programming language)

10.5515/kjkiees.2008.19.2.263

Cite

Citations (1)