• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.3
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• pp.313-318
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• 2018

A coaxial band rejection filter is designed and fabricated for a beam interacting cavity. The proposed filter has a quarter wavelength choke for the dominant mode of the cavity. The equivalent circuit of the coaxial band rejection filter is presented and the ABCD parameter os each part is derived to obtain the ABCD parameter of the entire filter. The scattering matrix was obtained from the ABCD matrix and the was simulated by MATLAB using the obtained scattering matrix. The coaxial band rejection filter structure was simulated using HFSS, and the results confirmed the simulation using the equivalent circuit was useful. The designed coaxial band rejection filter was fabricated with 6-1/8 flange. The fabricated filter was measured using a transition from 6-1/8 flange to N-type flange. The insertion loss of the fabricated filter is greater than 25 dB in the dominant mode of the cavity and less than 0.25 dB in the first higher order mode. The measurement results are in good agreement with the simulated results and meet the design specification.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.1
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• pp.90-97
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• 1992

An estimation method for the amplitude and phase response of transmission line is discussed. and applied to narrow band ISDN subscriber line. The ABCD parameters of line are evaluated from four impedance values: the standard termination impedence at activated and deactivated stares, and the input impedances of line which can be estimated at each state. Estimating input impedence, the “chirp” signal is used as incident signal and noise effect can be reduced by ensemble averaging. These ABCD parameter estimations might be applicable to ether uniform or nonuniform line. Cleary the magnitude and phase response can be obtained from estimated ABCD parameters. The numerical simulation results for N ISDN subscriber line model are included, and the estimation error introduced by deviation in load impedence is also anlyzed.

• 전자공학회논문지 IE
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• v.48 no.3
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• pp.10-15
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• 2011

In the case of designing an acoustic transducer for high power application, we usually aim to transfer the source electric energy to the output acoustic energy as large as possible. For this purpose, we should match the impedance of the power amplifier to the impedance combined with the acoustic transducer impedance and the radiation impedance. Especially if we have electrical source with almost zero impedance, we need improve the power factor of the acoustic transducer in the load. In this paper, we propose a broad band impedance matching method by the improvement of power factor, which applies ABCD matrix.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.4 s.95
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• pp.402-409
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• 2005

In analog and digital electronic systems, crosstalk between transmission lines on the printed circuit board can degrade the performance of equipment operations. This paper presents a technique to analyze the effects of via fence, which is based on additional transmission lines grounded by vias. The technique is composed of a circuit concept approach for transmission line sections md an impedance modeling of via hole sections. All sections are represented by ABCD parameters and they are cascaded. Finally, this technique was verified by comparing the measurement results with the simulation ones.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.11
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• pp.1318-1326
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• 2007

Simple practical design method is proposed for the waffle-iron waveguide filter. The design procedure comprises two steps. The first step is to calculate the K-inverter based on the transformed ABCD parameter from the S parameter for the single window of waffle-iron structure by use of EM S/W tool. The second step is to optimize the size of the windows such that the calculated K inverters may be in accord with the distributed constant prototype filter. In order to validate the design method, a waffle-iron filter for satellite communications over the Ka band is designed and fabricated. The measured results are in good agreement with the calculated ones.

• Journal of Advanced Navigation Technology
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• v.19 no.3
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• pp.224-229
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• 2015

In this paper, we derived the design equation and implemented the unequal Gysel power divider that is one external resistors using the ABCD parameters analysis. Conventional unequal Gysel divider is difficult to obtain the characteristics of isolation and return loss at between output ports because it can't select a theoretical value of external resistor. To solve those problems, we design the new unequal Gysel power divider with transmission lines and one external resistor that has the characteristics of conventional unequal Gysel divider. To validate this design method, we simulated and measured an 4: 1 unequal Gysel power divider at the center frequency 1 GHz. The measured performances agreed well with the simulation results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.10
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• pp.1122-1128
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• 2008

A novel tunable bandstop filter was proposed. It is composed of a right-handed transmission line, which has lowpass characteristics, and a left-handed transmission line which has highpass characteristics. Dispersion relations for the unit cells of RHTL and LHTL were derived by the method of ABCD parameter analysis. Varactor diodes and chip inductors were used to make the unit cells of RHTL and LHTL. A tunable bandstop filter was designed and fabricated by the parallel connection of RHTL and LHTL. The measured results of the proposed tunable bandstop filter are agreed well with the simulated results.

• Journal of Korea Water Resources Association
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• v.51 no.6
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• pp.523-533
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• 2018

The objective of this study is to analyze uncertainties of ensemble-based streamflow prediction method for model parameters and input data. ESP (Ensemble Streamflow Prediction) and BAYES-ESP (Bayesian-ESP) based on ABCD rainfall-runoff model were selected as streamflow prediction method. GLUE (Generalized Likelihood Uncertainty Estimation) was applied for the analysis of parameter uncertainty. The analysis of input uncertainty was performed according to the duration of meteorological scenarios for ESP. The result showed that parameter uncertainty was much more significant than input uncertainty for the ensemble-based streamflow prediction. It also indicated that the duration of observed meteorological data was appropriate to using more than 20 years. And the BAYES-ESP was effective to reduce uncertainty of ESP method. It is concluded that this analysis is meaningful for elaborating characteristics of ESP method and error factors of ensemble-based streamflow prediction method.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.10
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• pp.1344-1352
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• 2018

In this paper, we propose a two-port S-parameter data to diagnose the fault conditions of a single-phase transformer. Using the S-parameters we can measure the reflection and transmission characteristics of signal power at the port of a transformer, which can also be converted into ABCD parameters and Z parameters through a well-known conversion formulas. Transformer fault diagnoses can be performed based on the intuitive and qualitative/quantitative characteristics of the these parameters. In addition, we can obtain wide frequency characteristics at the primary and secondary sides of the transformer, which can be used to get time domain responses using the inverse Fourier transformation with some specific input waveform. In order to verify the effectiveness of the proposed method, the fault conditions were analyzed in simulation and experiment for 3 kVA single phase transformer with 15: 5 turns ratio, and the validity of the proposed method was verified.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.4 s.334
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• pp.45-52
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• 2005

This paper presents the characterization of through hole vias on printed circuit board (PCB) through the time domain and frequency domain measurements. The time domain measurement was performed on a single via using the TDR, and the model parameters were extracted by the fitting simulation using HSPICE. The frequency domain measurement was also performed by using 2 port VNA, and the model parameters were extracted by fitting simulation with ADS. Using the ABCD matrices, the do-embedding equations were derived probing in the same plane in the VNA measurement. Based on the single via characterization, the differential via characterization was also performed by using TDR measurements. The time domain measurements were performed by using the odd mode and even mode sources in TDR module, and the Parameter values were extracted by fitting with HSPICE. Comparing measurements with simulations, the maximum calculated differences were $14\%$ for single vias and $17\%$ for differential vias.