• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.13 no.11
• /
• pp.2267-2272
• /
• 2009

The six-port direct conversion receiver front-end that is comprised of a carrier recovery and a phase shifter, which gets the same structure with six-port phase correlator using the multi-layer coupled line, was designed and fabricated in this paper. The six-port element that is comprised of the power divider and the hybrid coupler is designed by multi-layer coupled line structure. The multi-coupled structure is utilized as the basic structure in receiver phase correlator, carrier recovery circuit and phase shifter. The receiver front-end with the same multi-layer coupled line structure for the receiver elements shows the simple structure and no difficulty in integration. The fabricated multi-layer coupled six-port receiver front-end re-generates the carrier signal with a constant phase and demodulates the PSK transmission signal.

• Proceedings of the IEEK Conference
• /
• 2002.07a
• /
• pp.523-526
• /
• 2002

The crosstalk among coupled microstrip lines is the major limiting factors of signal qualities in the high-speed digital and communication equipment. In this paper, a three-dimensional finite difference time domain (FDTD) method is applied to analyze the crosstalk between the coupled microstrip lines. The proposed structures of the coupled microstrip lines are investigated to reduce the coupling in a simple way by modifying their ground plane with an optimum gap. The examples of these structures with the different sizes of the gaps on their ground plane are studied. These structures are considered as the four-port network to evaluate transmission efficiency, near- and far-end crosstalk. Gaussian pulse is excited to evaluate the frequency characteristics from dc to 30 ㎓. The transmission efficiency, near- and far-end crosstalk of each structure of the coupled microstrip lines are demonstrated. The numerical results of this study show that the majority of crosstalk is the far-end crosstalk. The usage of the optimum gap on the ground plane can reduce the far-end crosstalk of the coupled microstrip lines while the transmission efficiency is nearly equal.

• ETRI Journal
• /
• v.27 no.5
• /
• pp.643-646
• /
• 2005

This letter proposes a band-pass filter (BPF) with two transmission zeros based on a combination of parallel coupling and end coupling of half-wave transmission lines. The fabricated BPF exhibited a narrow bandwidth and two transmission zeros near the pass-band due to the end-coupled and shielding waveguide. At the center operation frequency of 60 GHz, the 20 dB bandwidth of the BPF is 1.0 GHz, which is almost 2% of the center operation frequency, and the insertion loss is 3.12 dB. Two transmission zeros reach approximately 40 dB at 58.5 and 62.5 GHz. The simulation results almost agree with the measured results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.17 no.10 s.113
• /
• pp.935-942
• /
• 2006

In this paper, a novel theory of realizing the series capacitor with broadside coupled suspended substrate stripline (BCSSS) is proposed. The proposed theory is relatively simple because the method of odd mode analysis is only applied: However, this theory supplies reliable result by considering the line effective width and end effect caused by the fringing field. The simulation results are presented to compare and analyze the characteristics of the ideal lumped capacitor and the coupled line capacitor. Also, the capacitive gap coupled line band-pass filter based on the proposed theory are designed and fabricated. The results prove successfully the validity of the proposed theory.

• Proceedings of the KIEE Conference
• /
• 2005.07b
• /
• pp.1086-1088
• /
• 2005

It is necessary to modify the state-of-the-art of vector control theory, because of the phase asymmetry(static end effect) in the Linear Induction Motor(LIM). The dynamic characteristic analysis method of the vector controlled LIM using coupled FEM and control algorithm taking into account the movement is proposed. The focus of this paper is the analysis relative to phenomena of static end effect due to the motor structure. To prove the propriety of the proposed method, the Digital Signal Processor(DSP) installed experimental devices are equipped and the experiment is performed.

• Structural Engineering and Mechanics
• /
• v.41 no.1
• /
• pp.67-81
• /
• 2012

Differential Quadrature Method (DQM) is a powerful method which can be used to solve numerical problems in the analysis of structural and dynamical systems. In this study the governing equation which represents the free vibration of coupled shear walls is solved using the DQM method. A one-dimensional model has been used in this study. At the end of study various examples are presented to verify the accuracy of the method.

• Journal of the Korean Institute of Telematics and Electronics T
• /
• v.36T no.1
• /
• pp.79-85
• /
• 1999

The propagation properties of the high speed pulse signal in time domain using the equivalent circuits for the analysis by SPICE on the coupled microstrip lines are investigated. In this paper, the SPICE program is used for the crosstalk analysis on the coupled microstrip lines. The results of crosstalk of coupled microstrip lines compared to one by Branin and FDTD method. And the near-end and far-end crosstalk on coupled lines are analyzed for the square pulse and trapezoidal pulse. The results of this paper are apply To the determination for the geometric structure and the frequency of signal pulse in design of MIC and MMIC by the CAD program.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.20 no.5
• /
• pp.1383-1391
• /
• 1996

The steady-state response for a coupled structure-acoustic-cavity systme has been investigated by numerical technique using a directly coupled finite element method(FEM) and Boundary Element Method(BEM) model. The Laplace tranformed matrix equations for the structure and the acoustic cavity are coupled directly satisfying the necessary equilibrium and compatibility conditions. The coupled FEM-BEM code is verified by comparing its prediction for an example with known analytical, numerical and experimental results. The example involves a coupled structure-acoustic-cavity system which is a box-type cavity with one end as experimentally excited pinned-pinned plate.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
• /
• v.2 no.3
• /
• pp.48-60
• /
• 2003

With the rapid successful deployment of WLANs worldwide in numerous hotspots for high data rate, wireless access for data services has created the need to integrate the Cellular Networks with WLAN Networks. The integrated wireless environment will provide the end user a much better service experience along with a single subscription and a single bill. In this paper we focus on inter-working approaches, which combine WLANs and Cellular Networks into an integrated wireless environment capable of ubiquitous access to data services and very high data rates in hotspots areas. We first list the key requirements which are currently being standardized within the 30PP for integration with WLANs networks. We discuss two inter-working architectures namely loosely coupled and tightly coupled This paper will detail the loosely coupled inter-working approach while briefly discussing the tightly coupled inter-working. Finally, we will conclude that the loosely coupled approach is evolutionary and less intrusive than the tightly coupled approach.

• Bulletin of the Korean Chemical Society
• /
• v.35 no.9
• /
• pp.2694-2698
• /
• 2014

A multisegmented polystyrene (PS) with pH-cleavable ester and carbamate linkages was successfully synthesized by a combination of atom transfer radical polymerization (ATRP) and Cu(I)-catalyzed 1,3-dipolar cycloaddition of azide and alkynes (click chemistry). ATRP was employed to synthesize polystyrene from hydroxyl-terminated initiator using CuBr/N,N,N',N",N"-pentamethyldiethylenetriamine (PMDETA) as the catalyst. The reaction of the resulting PS with sodium azide yielded the azido-terminated polymer. The hydroxyl group in the other end of the polymer was reacted with 4-nitrophenyl chloroformate (NPC), followed by reaction with propargylamine to produce an alkyne end group with a carbamate linkage. The PS with an alkyne group in one end and an azide group in the other end was then self-coupled in the presence of CuBr/2,2'-bipyridyl (bpy) in DMF to yield a desired multisegmented PS. Molecular weight and molecular weight distribution of the self-coupled polymer increased with time, as in the typical step-growth-type polymerization processes. Finally, we demonstrated that the ester and carbamate linkages of the multisegmented PS were hydrolyzed in the presence of HCl to yield individual PS chains.