• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.2
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• pp.114-120
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• 2008

This paper proposed the band pass filter(BPF) with feeding structure using $\pi$-type transmission line by means of transforming the input/output coupled-lines of the half wavelength parallel coupled-line BPF into K-inverter, then substituting $\pi$-type transmission line equivalence for K-inverter. The proposed method supplies solution with what the half wavelength parallel coupled-line BPF's input/output coupled-lines are realized. Also it can quite reduce efforts and time needed to optimize filter performance when is compared to reported method using tapped line structure because formulas is very simple and accurate. On the basic of the proposed method, the BPF with feeding structure using $\pi$-type transmission line has been designed and fabricated. The validity of proposed method was proven by the measured result.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.3
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• pp.449-459
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• 1999

The scattering problems from electromagnetic absorbers can be greatly simplified using the transmission line approximations (TLA) and effective medium theory. This method has been widely used for the absorber design because of its very simple calculation and intuitional approach, while numerical analysis needs the tremendous computation requirements, This paper examined the accuracy and limitations originated by the intrinsic approximation limits of TLA by comparison with FEM results for various absorber design examples. It was found that the TLA result is valid when λ $\geq$ 2p, where λ is the wavelength of the interested upper frequency and p is the distance between two periodic cone arrays. Therefore, the electromagnetic absorbers having high material properties and big base-area commonly do not meet this condition, and the electromagnetic scattering from those absorbers must be evaluated by the numerical analysis in those cases.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.5
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• pp.187-195
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• 2005

A new segmentation-based image coding method which no needs transmission of contour data is proposed. The shape information acts as bottleneck in the segmentation-based video coding because it has much portion of transmission data. The proposed method segments a previous decoded frame, instead of a current frame. As a result, there is no need for transmission of contour information to a decoder. Therefore, the saved bits can be assigned to encode other information such as error signals. As shown in experiment results, if data rate is very highly increased due to abrupt motion under very low bit rate coding having limited transmission bits, PSNR of conventional block-based method go down about 20dB, while the proposed method shows a good reconstruction quality without rapid PSNR drop.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.2211_2212
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• 2009

본 논문에서는 GaAs-Transistor가 접합된 전송선로 사이에서 발생되는 Crosstalk의 영향에 관한 연구를 하였다. 이 모델의 해석을 위해 인접선에서의 Crosstalk의 이론적인 접근을 하고, 3D Full Wave 시뮬레이션과 Circuit 시뮬레이션을 통해 해석하는 Crosstalk의 해석방법에 대한 모델을 제시하고자 한다. 또한 Coupling 된 Solder Bump의 Equivalent Circuit Model을 제시함으로써 Solder Bump의 Coupling이 Crosstalk의 영향에 미치는 영향에 대해 규명하고자 한다.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.6
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• pp.97-102
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• 1985

A new microwave transmission line frequency discriminator in MIC is described, which is composed of a branch-line hybrid 3dB coupler, a λ/2-short stub and a λ/4-opcn stub. It is experimentally verified that the discriminator is linear in a 400 MHz bandwidth at center frequency 4.94 GHz and has return loss more than 15dB in that range.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.7
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• pp.675-682
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• 2011

This paper presents two ground plane effects due to the size of two rectangular apertures for two-wire transmission line with equal line length crossing the changeable rectangular apertures in infinite ground planes. The CST MWS is used to determine the characteristics of the insertion loss of the transmission line from the load section in accordance with the ground plane aperture size. The results show that the insertion gain and the insertion loss are periodically observed for the multiple frequency of the half wavelength resonance by the wire length when the transmission line is nearby to horizontal side or vertical side of the aperture. The measurements of the insertion loss are performed to verify the theoretical analysis.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.3
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• pp.425-431
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• 2001

In this paper, on aperture-coupled microstrip cylindrical dielectric resonant antenna(DRA) consisting of dielectric material with permittivity ${\epsilon}_{r}$ = 36 is designed and fabricated fir wireless LAN. First of all, the feedline length, width, slot length and width of the feeding element were calculated using the theory of microstrip transmission line. Radiation element is designed using the theory of cylindrical dielectric cavity, Resonant frequency of the fabricated cylindrical DRA is 2.449 GHz and VSWR, return loss and bandwidth is 1.009, -47 dB and 70 MHz, respectively. Front-to-back radiation ratio is about 12 dB and 3 dB beamwidth of E-plane and H-plane is 110$^{\circ}$ and 90$^{\circ}$ , respectively.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.109-112
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• 2001

본 논문은 고속 전력선 통신을 위한 기댐으로 주파수 범위 0∼30MHz에서 BER 개선을 목적으로 DMT 방식을 실험하였다. 송신단에서 길쌈 부호화 방법을 사용했고, 수신단에서는 비터비 알고리즘을 이용해서 복호화 하였으며, 프레임 동기를 위해서 cyclic prefix를 사용하였다. 전력선 채널 특성을 고려하여 거리에 따른 채널 모의실험을 통해서, 코헤어런트 신호를 분석한 결과에 의해 BER을 우수하게 전송시키는 변조 방식을 분석함으로써 전력선상에서 DMT 특성을 이론적으로 분석하여 정보 전달 범위의 효과를 높일 수 있는 방안을 제시하였다.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.1
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• pp.52-57
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• 2015

In this paper, we studies on the RF characteristics of the transmission line employing IPACD (inverted periodically arrayed capacitive devices) on MMIC (monolithic microwave integrated circuit) for application to wireless communication system. According to measured results, the novel transmission line employing IPACD showed a wavelength much shorter than conventional transmission lines. In addition, the IPACD structure showed an effective permittivity much higher than conventional ones. We also extracted the bandwidth characteristic of the IPACD structure using equivalent circuit analysis. According to the results, the cut-off frequency of the proposed structure was 129.2 GHz.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2000.11a
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• pp.99-103
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• 2000

본 논문에서는 FM Reflectometry를 이용하여 마이크로파 대역에서 다양한 전송선로의 분산특성을 측정하였다. 실험에 사용된 전송선로는 도파관에 금속봉이 주기적으로 위치한 구조로서 Gyro-TWT의 iinteractio circuit으로 사용되기 위해서 설계되었다. 도파관에 금속봉이 주기적으로 위치한 구조의 group velocity를 측정하기 위해서 FM Reflectometry와 기존의 Network Analyzer Time Domain 기능이 사용되어졌으며, phase velocity를 측정하기위해 서 short metal plate를 이용한 방법과 High Frequency Structure Simulator (HFSS)가 이용되었다 측정된 결과는 이론치, 시뮬레이션과 비교했으며 각각의 비교는 잘 일치함을 보여 FM Reflectometry기법이 분산특성 측정에 사용되어질 수 있음을 보였다.