• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.7 no.5
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• pp.430-439
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• 1996

In printed circuit board (PCB) design, it is necessary to predict the crosstalk effect among traces on the circuitary behavior. In this paper, crosstalk between parallel or crossing traces was treated by the finite difference time domain (FDTD) method. They are the typical models of PCB traces and the crosstalk is a major contributor in the creation of electromagnetic interference (EMI). The crosstalk effect was computed for the variation of distance spacing and length of parallel traces and crossing traces. The results in time and frequency domain are discussed and compared with those using MDS(microwave design system) and HFSS(high frequency structure simulator). The comparison shows that the FDTD method can be of wide application in analysis model and save the time required for calculation.

• Journal of electromagnetic engineering and science
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• v.9 no.3
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• pp.164-173
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• 2009

In this paper, two new circuit structures for European and U.S. ultra-wide band(UWB) bandpass filters(BPFs) with sharp roll-off characteristics are introduced. We show first that the ultra-wide bandpass property is obtained from a $\lambda$/4 open T resonator with a capacitively coupled $\lambda$/4 short-circuited line, which provides two attenuation poles at lower and upper cutoff frequencies. Then, two identical capacitively coupled input/output lines, which can be $\lambda$/4-length open ends or $\lambda$/2-length short ends, with the T-resonator, are adopted to suppress lower and higher frequency components outside of the pass band. There is coupling between the input and output lines providing two additional transmission zeros in the lower and upper transition bands of the filter. Since the coupling between the T-resonator with the $\lambda$/4 short-circuited line and the input/output lines limits the bandwidth of the filter to the European UWB band, both the $\lambda$/4 short-circuited line and the input/output lines are inserted between the two stacked T-resonators for the U.S. UWB band. The filter structures are simulated with ADS and HFSS and realized with low-temperature co-fired ceramic(LTCC) green tape which has the dielectric constant of 7.8. Measurement results agree well with HFSS simulation results.

• Journal of electromagnetic engineering and science
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• v.10 no.3
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• pp.92-98
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• 2010

A new wideband bandstop filter(BSF) with a sharp roll-off characteristic is introduced in a stripline structure in this paper. The BSF consists of two sections: the first is two capacitively coupled $\lambda/4$ short-circuited lines with opposite ground positions, while the second is a capacitively coupled $\lambda/4$ short-circuited line. The BSF provides three transmission zeros within the stopband and better than 22 dB rejection over the whole wireless local area network (WLAN) band from 5.15 to 5.825 GHz. The BSF, cascaded to an U.S. ultra-wideband(UWB: 3.1~10.6 GHz) band-pass filter(BPF), is simulated with HFSS and realized with low-temperature co-fired ceramic(LTCC) green tape with a dielectric constant of 7.8. The measurement results agree well with the HFSS simulation results. The size of the UWB BPF including the BSF is $3{\times}6.3\times0.45\;mm^3$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.12
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• pp.3608-3613
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• 2009

In this paper, we propose a mobile Radio Frequency Identification antenna for mobile hand set. The proposed antenna with directive radiation characteristics based on combination of electric-magnetic radiators can be installed in the mobile hand-set. The combination of PIFA antenna for electric radiator and loop antenna for magnetic radiator is presented and designed for료 m-RFID reader system. Target frequency band is 900-MHz band. and desired gain is 4dBi. The antenna is simulated using Ansoft HFSS software and shows expected results. The antenna is also manufactured using FR4-epoxy circuit board (h=1 mm, $\varepsilon_{\tau}=4.4$). There are good agreements between the simulated and measured VSWR curves and radiation characteristics.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.9
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• pp.873-881
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• 2002

In this paper, the rectangular reflector antenna with 8-dipole array for PCS band (1,750 MHz ~ l,870 MHz) and IMT-2000 band(1,885 MHz ~ 2,200 MHz) is designed and the radiation characteristics are analyzed using the method of moments and HFSS(High Frequency Structure Simulator). To verify the analysis results, rectangular reflector antenna with 8-dipole array is fabricated and the calculated results are compared with the measured results. The measured results show good agreement with the calculated results. As a result of measurements, bandwidth(VSWR< 1.5) of 450 MHz is achieved at PCS and IMT-2000 band and gain is 16 dBi. The designed antenna can be used as the base station antenna for PCS/IMT-2000.

• Journal of the Korea Institute of Military Science and Technology
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• v.4 no.1
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• pp.124-136
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• 2001

In this paper, we designed and manufactured the Ku-band circular waveguide antenna to do wireless communication with a ground radar as on-board antenna of missile. Using the MATLAB and the HFSS, we designed the circular polarizer which has a characteristic of circular polarization and broadband using the capacitive pin method, the feeder to feed coaxial line to circular waveguide, and a stopper to prevent a conductor material from being inserted. Then we simulated the designed antenna using the HFSS, obtained the gain and the radiation pattern. Because of a difficulty of manufacture, we established a manufacture process procedure. Antenna is manufactured with this procedure, test results of the manufactured antenna are the axial ratio of 1.37 ~ 1.72, the 3 ㏈ beamwidth of $72.23^{\circ}{\sim}78.54^{\circ},$ and the gain of 3.26 ~ 4.61 ㏈ within frequency band. We knew that these results are similar with simulation results. Also, we confirmed that the manufactured antenna is satisfied with requirement conditions through performance test, environmental test and flight test.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.6B
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• pp.1123-1133
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• 1999

In this paper, we applied mode matching and generalized scattering matrix methods to three plane mode matching method for analyzing T-junctions. We calculated all scattering matrix elements by only three times and considered several incident modes. By proposed analysis method, we could analyze various waveguide discontinuity structures more conveniently and accurately. Using the stepped T-junction, we would be able to reduce the reflection coefficient at an input port and use it over wider band. Simulated and HFSS data of T-junctions are compared, showing good agreement for scattering matrix elements. Considering step numbers, height, length and position, we extracted for optimum dimensions and equivalent circuit parameters.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.3 no.2
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• pp.25-30
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• 2010

In this paper, a novel notch resonator is proposed based on Rectanglar Split Ring Resonator (R-RSS) element. We represented the electrical characteristics for R-SRR elements coupled with microstrip line, and measured result is compared with electromagnetic simulation (HFSS) result. We also solved equivalent circuit for R-SRR element, and also discussed influences of change structural parameters of R-SRR. the size of R-SRR is the most important parameters for frequency tuning. Also we can make tunable resonator form the basic structure. This novel resonator can apply to design of tunable bandpass filter and voltage control oscillator.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.4
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• pp.765-771
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• 2015

In this paper, a dual-band arc-shaped monopole antenna for WLAN(Wireless Local Area Networks) applications. The proposed antenna is based on CPW-fed structure, and composed of two-arc shaped of radiating patch and ground plane. To obtain the optimized parameters, we used the simulator, Ansoft's High Frequency Structure Simulator (HFSS) and found the parameters that greatly effect antenna characteristics. Using optimal parameters, the antenna is fabricated. The numerical and experiment results demonstrated that the propnosed antenna satisfied the -10 dB impedance bandwidth requirement while simultaneously covering the WLAN bands. And measured results of gain and radiation patterns characteristics displayed determined for opeating bands.

• Journal of Advanced Navigation Technology
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• v.20 no.1
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• pp.93-98
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• 2016

The purpose of this study is to design for MOB antenna attached on safety helmet using microstrip patch antenna. The patch antenna is fabricated in 0.2 mm FR-4 substrate with $64{\times}64mm$ size. The proposed antenna is based on a slot-ring design which cover Inmarsat (1.52 ~ 1.65 GHz) and GPS (1.575 GHz) frequency band. To obtain the optimized parameters, HFSS simulator is used, and antenna is designed by optimized parameters. After antenna was etched, SMA connector was attached to the microstrip feeding line and the result between antenna simulation and measurement was analyzed. Proposed antenna is satisfied the -10 dB bandwidth requirement while simultaneously covering the 1.53 ~ 1.65 GHz.