• The Journal of the Korea Contents Association
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• v.7 no.3
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• pp.60-67
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• 2007

This research studies and analyzes the current trends and the frequency allocation bands for digital cordless phone(DCP) in other country. From these results, we propose 1.7GHz & 2.4GHz as a effective candidate frequency band for domestic DCP. A proposed 1.7GHz is expected to introduce DECT system of Europe. Therefore it is necessary to make an analysis of interference between 1.7GHz band and an adjacent IMT-2000 band. In this paper, we proposed the allocation of channel for 1.7GHz on the basis of the analysis of frequency interference between 1.7GHz band and an adjacent IMT-2000 band.

• Journal of IKEEE
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• v.27 no.4
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• pp.405-410
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• 2023

This paper presents a novel method of implementing a dual-band antenna using a square patch with an inset feed structure. The proposed method is to simply design a dual-band antenna using an asymmetric inset structure with different lengths of slots dug into the patch for inset feeding. To verify the proposed method, a dual-band inset patch antenna supporting 1.57 GHz GPS and 2.4 GHz WiFi bands was designed and manufactured on a 1 mm thick FR4 substrate. From measurement, it was confirmed that the frequency bands of the antenna that satisfy a return loss of -10dB or less are 1.55~1.57GHz and 2.41~2.45GHz, which has dual-band characteristics. Using the proposed method, it is possible to simply implement a dual-band antenna using inset feeding, and it is expected to be utilized in a variety of application fields.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.5
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• pp.528-537
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• 2011

In this paper, a broadband antenna of the CPW structure with a band-notched characteristic is presented. To obtain this characteristic, the complementary split ring resonator(CSRR) is inserted in the ground plane. In addition, the IEEE 802.11a WLAN band(5.15～5.825 GHz) appears in the band-notched characteristic. The proposed antenna dimension is $36{\times}60{\times}1.6\;mm^3$, and it is designed on the FR-4 substrate having a relative dielectric constant of 4.4. The designed antenna shows that the resonant frequency is 2.03～10.78 GHz below the return loss of -10 dB and a VSWR less than 2 was satisfied. As a result, the proposed CSRR has a band-notched characteristic in the range of 4.917～6.017 GHz which the center frequency is about 5.4 GHz band.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.8
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• pp.3623-3627
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• 2012

The modern society has become full-fledged entry into the information age since spread of Internet. In the information age, internet was developed from the wired access to the wireless Internet access. When a surge in demand for wireless Internet access, efficiency and performance of 2.4GHz band which leads to saturation of the communication was significantly fall. Accordingly, the communication of the 5GHz band came to be interested. In this paper, we studied the design and fabrication of u-slot microstrip patch antenna to be used in wireless communication systems operating at around 5GHz band. To obtain antenna parameters such as patch size, inter patch space, antenna was simulated by HFSS(High Frequency Structure Simulator). From these parameters, u-slot microstrip patch antenna is fabricated using FR-4 substrate of dielectric constant 4.4. The characteristics of fabricated antenna were analyzed by network analyzer.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.2
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• pp.56.3-56.3
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• 2015

한국우주전파관측망은 22GHz, 43GHz, 86GHz, 129GHz의 4주파수 동시관측 시스템을 운용하고 있다. 이 시스템으로부터 수신된 전파신호를 실시간으로 디지털 신호로 바꾸어 주는 장치인 샘플러의 국산화를 위하여, 우리는 3년간의 연구개발로 1GHz 샘플링을 할 수 있는 샘플링 장치를 설계/제작하였다. 그리고, 이를 연구 관측에 실제 적용할 수 있음을 보여 주었다. 본 연구에서는 한 단계 더 나아가 광대역 관측과 e-VLBI 구현을 위하여 전파관측 자료를 직접 첨단 연구망으로 보낼 수 있는 4GHz 샘플러를 개발 중에 있다. 이번 발표에서는 4GHz 샘플러에 대한 개발 현황 및 향후 계획을 소개한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.56-58
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• 2013

In this paper, a design method to obtain a band rejection characteristic in the 2.4-2.484 GHz WLAN band is studied for a series-fed dipole pair (SDP) antenna operating in the band of 1.7-2.7 GHz for mobile communication base station applications. The band rejection characteristic is achieved by inserting U-shaped slots on the coplanar strip line connecting the two dipole elements of the SDP antenna. The effects of the location and dimension of the slots on the band rejection characteristics are examined. The optimized SDP antenna with WLAN band rejection is fabricated on an FR4 substrate and the experimental results show that the antenna has a desired band rejection performance with a frequency band of 1.65-2.78 GHz (51.0%) for a VSWR < 2, and a rejection band of 2.39-2.54 GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.2
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• pp.138-144
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• 2008

In this paper, we propose a novel single-feed dual-band circular polarization square patch antenna for GPS(global positioning system)/DMB(digital multimedia broadcasting) receiver. The proposed antenna has folded slots at the 4 corners and a diagonal slot at the center of the square patch. The measured -10 dB impedance bandwidths of the proposed antenna were 84 MHz ranging from 1.516 GHz to 1.600 GHz for the low frequency band(GPS) and 109 MHz ranging from 2.596 GHz to 2.705 GHz for the high frequency band(DMB). The measured peak linear antenna gains of the proposed antenna were 6.23 dBi at 1.575 GHz for GPS and 6.97 dBi at 2.642 GHz for DMB band.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.2A
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• pp.213-219
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• 2007

In this paper, A novel structure of frequency doubler using Phase Delay line and $90^{\circ}$ Hybrid coupler at harmonic output have been designed and implemented to improve suppression. Proposed structure of frequency doubler improve output. coupling and fundamental suppression. Active frequency doubler with band from $2.13{\sim}2.15GHz\;to\;4.26{\sim}4.3GHz$ was designed and fabricated with 10dBm input power, 0.79dB conversion gain and -55.54dBc suppression at fundamental frequency, -44.76dBc suppression at third harmonic frequency 6.42GHz and -39.18dBc suppression at fourth harmonic frequency 8.56GHz.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.4
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• pp.27-30
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• 2016

in this paper, to improve the narrow bandwidth problem of the microstrip antenna for WLAN and WiFi dual band array antenna was designed to satisfy the bandwidth of 3.6GHz and 5.2GHz it contained with IEEE 802. 11. The substrate of proposed microstrip array antenna is FR-4(er=4.3) and $25mm{\times}45mm{\times}0.8mm$ size and thickness t=0.035mm, and the simulation was used for CST Microwave Studio 2014. input return loss compared -10dB less than operates at and when gain 3.6GHz 2.516dB, 5.2GHz showed the results of 3.581dB. the antenna designed to be miniaturized and the be used in electronic devices such as mobile phone.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.2 s.117
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• pp.158-165
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• 2007

In this paper, the circularly polarized $4{\times}4$ array antenna is proposed for the X-band. A single antenna consists of square patch and unequal cross-aperture coupled feeding. The RHCP(Right Handed Circularly Polarization) is generated by unequal cross-aperture coupled feeding. By reducing space among elements of way antenna from 0.8 ${\lambda}_0$ to 0.45 ${\lambda}_0$, the mounting area of array antenna is miniaturized. The $2{\times}2$ array antenna is designed using sequential rotation feeding network. The good level of gain, axial ratio, and impedance bandwidth are achieved. The $4{\times}4$ array antenna is extended by ${\lambda}/4$ transformer and T-junction power divider. The simulated maximum radiation gain is 15.09 dBi at 10 GHz. The simulated 3 dB Axial Ratio bandwidth is from 9.05 to 10.4 GHz(13.5%). Also the measured impedance bandwidth($VSWR{\leq}2$) of manufactured $4{\times}4$ array antenna is from 8.45 to 11.84 GHz(33.9%). The measured maximum radiation gain is 11.10 dBi at 10 GHz. The measured 3 dB Axial Ratio bandwidth is from 9.42 to 10.47 GHz(10.5%).