• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.2
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• pp.115-123
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• 2009

In this paper, we extract the parasitic elements of the transmission line with the defected ground structure(DGS) and the short-circuited comb line section using the Short-Open Calibration(SOC). The scattering matrixes of short, open and the distributed elements in microstrip line are measured by full electro-magnetic(EM) simulator and Vector Network Analyser(VNA). The electro-magnetic effects of the proposed structures are considered by the II and T equivalent circuits with frequency independent elements, and the relations between the measured scattering parameters and the elements in the circuits are shown by performing 2 port network analysis. Moreover, to design the 2.4 GHz bandpass filter with second order butterworth prototype, the proposed methods are applied. As results, the measured $S_{11}$ and $S_{21}$ indicate -20 dB and -1.3 dB at center frequency, and these are shown within 5 % error compare to the predicted results at $0.5{\sim}5\;GHz$.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.10
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• pp.2339-2344
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• 2014

of a microstrip transmission line, this transmission line can operate as the microstrip line or the coplanar line according to open or short connection between the ungrounded copper plane and grounded plane on the base plane. Two different type operation of the transmission line means that one transmission line can have two different characteristic impedances. This paper proposes and fabricates the circuit to be operated 2-ports power transmission line or 2-way power divider with the stable input matching characteristic by using this dual-impedance transmission line. The proposed circuit operates 2-ports power transmission line in case of the coplanar line or 2-way power divider line in case of the microstrip line. The fabricated circuit shows $S_{21}$ > -0.2 dB and $S_{11}$ < -15 dB above 700 MHz when the circuit operates 2-ports power transmission line. And, it is $S_{21}$ > -3.8 dB, $S_{11}$ < -10 dB and $S_{21}/S_{31}$ < ${\pm}0.3dB$ above 700 MHz when the circuit operates 2-way power divider.

• The Journal of the Korea Contents Association
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• v.9 no.12
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• pp.566-571
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• 2009

In this paper, microstrip bandpass filter combined DCRLH metameterial-cells with a hairpin resonator is designed and fabricated to be transferred only fundamental passband signal, and removed a spurious resonant mode occurring when filter design using a microstrip transmission line is done. The bandpass filter is composed of CCRLH hairpin resonator and DCRLH interdigit metameterial-cells. The hairpin resonator with CCRLH property is implemented between two DCRLH interdigit metameterial-cells with DCRLH property, which is parallel to input port and output port. The interdigit metameterial-cells suppress spurious harmonics occurring on the higher order frequency and improve a filter performance. Insertion loss of the fabricated microstrip bandpass filter on the passband from 1.91GHz to 2.41GHz is 0.2dB, and attenuation on the stopband from 3GHz to 7.7GHz is bellower than -30dB. Therefore, this filter has a good performance for both mobile communications of WCDMA and wireless internet of WiBro.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.223-227
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• 2001

To complement the narrow band characteristics of the microstrip patch antenna, the slot patch antenna was designed for the wide band characteristics. The microstrip slot patch antenna has wide band characteristics when the size of the slots and the feed line shapes are designed accordingly. In this study, various substrates as a epsilon-10, and a epoxy were used to design slot patch antennas. The feed line structure of the circular and square were also designed to have wide band. In the case of slot antennas with the circular patch shapes using epsilon-10 plate 50mm thickness with relative permittivity the 41% bandwidth on the 1.5∼2.28㎓ was shown. When an Epoxy plate 1.Sum thickness with relative permittivity 4.75 is used to construct a circular slot antenna with a square patch form, the frequency band width was obtained 77% as the 1.2∼2.7㎓ frequency range. These results are coincided well with the theoretical results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.8 no.5
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• pp.516-524
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• 1997

The propagation properties of various pulse signal types(square pulse, Gaussian pulse, trapezoid pulse, RF pulse) on coupled microstrip lines are investigated. Numerical integration technique which has its accuracy and is easily simulated, is used to obtain the time domain response of pulse signals. Frequency-dependent characteristics of coupled microstrip line is obtained using Jansen's approximate equation. The propagation properties of pulse signal on coupled microstrip lines is analyzed regarding to its geometric structure (relative permittivity ${varepsilon}_r$ substrate height h, strip width w of the microstrip line) and pulse width ${\tau}$ of signal pulse. The simulation results show that space between two lines is very significant parameter in pulse distortion in comparison of any other parameters. The results of this paper are compatible to the trade-off determination of relative permittivity, substrate height, strip width and pulse width of signal pulse when a design of MIC and MMIC is necessary.

• 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.397-401
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• 2005

In this paper, a slot-coupled microstrip antenna with switchable polarization is proposed for the polarization diversity applications in the complicated communication environment. The proposed antenna is fed by a microstrip line through one of two slots located with the interval of $\lambda{g}/4$ in the ground plane. By switching the PIN diode between opened and shorted termination which is located at the tip of the microstrip line, the switching function between horizontal and vertical polarization was confirmed experimentally. The measured resonant frequencies of the fabricated antenna are $2.41\;\cal{GHz}\;2.40\;\cal{GHz}$ and the cross polarization levels are $19\;\cal{dB},\;23\;\cal{dB},\;the\;-10\;\cal{dB}$ return loss bandwidths are $95\;\cal{MHz}\;100\;\cal{MHz}$ in horizontal and vertical polarization, respectively, and the antenna gain is almost $6\;\cal{dBi}$.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.350-353
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• 2003

In this paper, we designed and implemented a 10dB directional coupler with high directivity using branch line structure. The characteristic impedance of parallel branch line for 10 dB directional coupler is about 150 $\Omega$. To realize high characteristic impedance in microstrip line, we used the coupled line structure. The directional coupler were implemental and measured. The measured results show that the directivity is high than 24 dB.

• Journal of the Microelectronics and Packaging Society
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• v.8 no.3
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• pp.69-75
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• 2001

Photoimageable thick film technology is a new technology in that the lithography process such as exposure and development is applied to the conventional thick film process. Line resolution of 25 $\mu\textrm{m}$ width and 25 $\mu\textrm{m}$ space could be obtained by laminating green sheet, printing photoimageable Ag paste, exposing the test patterns, developing, and co-firing. In case of using the alumina substrate, 20 $\mu\textrm{m}$ fine line could be also obtained by similar process. Test results showed that exposing power density and developing time were the most important processing parameters for the fine line formation. Microstrip and series gap resonators with well-defined line morphology and good transmission characteristics in high frequency were formed by this new technology, and thereby dielectric constant and loss of test substrate were calculated.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.2
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• pp.374-379
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• 2006

In this paper, the high Gain and the wideband microstrip patch antenna, which is applicable to 5 GHz band wireless LAN, is designed and fabricated. Firstly to widen the bandwidth of microstrip antenna, U-Slot in rectangular form patch is inserted and used the microstrip line-Coaxial probe feeding method. Secondly, the antenna gain is improved to be embodied in $2{\times}2$ array form. As a result, in this paper, is designed and fabricated 5 GHz Band wideband U-Slot $2{\times}2$ array patch antenna using microstrip line-coaxial probe feeder. The U-Slot $2{\times}2$ array patch antenna were fabricated on the PEC using press-technique that is based on the simulation results. And the Anritsu 37169A vector network analyzer has been used in measurement of a prototype antenna. As a result, it was measured that the superior characteristic of wideband showing approximately 1 GHz ($5.110 GHz{\sim} 6.142 GHz$) of input return loss (VSWR < 2) in resonant frequency of 5 GHz band. And the antenna gain is 13 dBi, in both the E-plane and H-plane measured at 5.15 GHz, 5.35 GHz, 5.50 GHz, and 5.87 GHz.

• Journal of Korea Society of Industrial Information Systems
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• v.4 no.4
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• pp.111-116
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• 1999

In this paper, the electromagnetically coupled microstrip dipole antenna by adapting one parasitic metal-strip(dipole) between the microstrip transmission line open end and the radiating microstrip dipole antenna is presented for the bandwidth improvement The microstrip dipole antenna is simulated using Ensemble 51 simulation package The effects of varying several physical parameters, such as the lengths of radiating dipole and parasitic dipole and the width of parasitic dipole are investigated The bandwidth behavior of the 3-layer optimum antenna is compared with that of 2-layer antenna without the parasitic dipole. Experimental result for the obtained broadband performance is presented and discussed.