• Journal of Advanced Navigation Technology
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• v.21 no.2
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• pp.193-199
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• 2017

In the paper, a dual band-notched monopole antenna is proposed for 2.4 GHz WLAN (2.4 ~ 2.484 GHz) and UWB (3.1 ~ 10.6 GHz) applications. The 3.5 GHz WiMAX band notched characteristic is achived by a pair of L-shaped slots instead of the previous U-shaped slot on the center of the radiating patch, whereas the 7.5 GHz band notched characteristic is achived by C-shaped strip resonator placed near to the microstrip feed line. The measured impedance bandwidth (${\mid}S_{11}{\mid}{\leq}-10dB$) is 8.62 GHz (2.38 ~ 11 GHz) which is sufficient to cover 2.4 GHz WLAN and UWB band, while measured band-notched bandwidths for 3.5 GHz WiMAX and 7.5 GHz bnad are 1.13 GHz (3.15 ~ 4.28 GHz) and 800 MHz (7.2 ~ 8 GHz) respectively. In particular, it has been observed that antenna has a good omnidirectional radiation patterns and higher gain of 2.51 ~ 6.81 dBi over the entire frequency band of interest.

• Journal of Advanced Navigation Technology
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• v.22 no.1
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• pp.31-36
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• 2018

In this paper, we designed and implemented an ultra wideband(UWB) antenna with band rejection characteristics. The proposed antenna consists of a planar radiation patch with slots and ground planes on both sides. Due to the slots in the radiation patch, the antenna shows band rejection characteristics. U-type slot contributes for wireless local area network(WLAN, 5.15~5.825 GHz) band rejection and n-type slot contributes for X-Band(7.25~8.395 GHz) band rejection. To make voltage standing wave ratio(VSWR) less than 2.0 for UWB frequency band except rejection bands, the shapes of planar radiation patch and ground plane was modified. The Ansoft 's high frequency structure simulator(HFSS) was used for the design process and simulations of the proposed antenna. The simulated antenna showed VSWR less than 2.0 for all UWB band excepts for dual rejection bands of 5.15 ~ 5.94 GHz and 7.02 ~ 8.45 GHz. And measured VSWR for the implemented antenna is less than 2.0 for all UWB band of 3.10~10.60 GHz excluding dual rejection bands of 5.12~5.95 GHz and 7.20~8.58 GHz.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.9B
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• pp.1196-1202
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• 2001

본 논문에서는 대역통과 필터특성을 위해 통과대역의 상단과 하단의 저지대역에서 감쇄극을 갖는 두 종류의 새로운 마이크로스트립 구조를 제안한다. 이 구조는 TEM모드의 유전체 공진기를 마이크로스트립선로에 용량성 또는 유도성의 병렬 포스트와 연결하여 구성된다. 제안한 구조에 대한 등가회로를 추출하였다. 이 구조의 S-파라미터를 실험과 등가회로 시뮬레이션으로 구하였고, 그리고 유도성포스트의 경우는 3D-FDTD 계산을 추가하여 서로를 비교하였는데 등가회로 모델이 이들 결과와 매우 잘 일치하였다.

• Journal of the Korean Institute of Telematics and Electronics
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• v.7 no.1
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• pp.1-8
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• 1970

The band-stop filters which resonate at intervals of one-quarters, and three-quarters guide-wave length are designed and its frequency characteristics are measured. 2K25 klystrons (at 8000MC) were used as microwaves source. This bandstop filters were designed from low pass prototype and the Impedance of Impedance of these filters was made to be equal to one of the low pass prototype. It is demonstrated that the filters considered here, have narrow stop bandwidths and sharp characteristics in the stop band.

• Journal of the Korean Ceramic Society
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• v.40 no.11
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• pp.1090-1095
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• 2003

In this paper, the modeling and design of high-Q multilayer passives and multilayer diplexer for GSM/DCS applications designed and fabricated using these passives have been investigated.. To miniaturize the system, configurations of inductor and capacitor have involved a square spiral structure and a vertically-interdigitated capacitor similar to 3D interdigital structure, respectively. Multilayer diplexers for GSM/DCS applications were designed and fabricated to apply high-Q multilayer passives to practical systems, which were designed by the proposed structural and equivalent circuit model. LPF for GSM band had the passband insertion loss of less than 0.55 dB, the return loss of more than 12 dB, and the isolation level of more than 26 dB by locating attenuation pole at 1800 MHz. HPF for DCS band had the passband insertion loss of less than 0.82 dB, the return loss of more than 11 dB, and the isolation level of more than 38 dB by locating attenuation pole at 930 MHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.7
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• pp.796-808
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• 2007

In this paper, two novel compact microstrip bandstop filters using complimentary split ring resonators(CSRRs) and spiral resonators is proposed. The first one is the bandstop filter using an array of CSRRs etched on the center line of a microstrip. The bandstop is due to the presence of negative effective permittivity and positive permeability near resonant frequency which prevent the wave propagation. The second on is the bandstop filter using an array of spiral resonators etched on the center line of a microstrip. The bandstop is due to the self-resonance of spiral circuit. We have achieved controllable resonance frequency and bandwidth, super compact dimension, low insertion losses in the passband and high level of rejection in the stopband with sharp cutoff. The electrical sizes of two proposed filter are very small. Additionally, they can be easily fabricated and compatible with MMIC or PCB technology.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.2 s.93
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• pp.199-203
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• 2005

In this paper, a novel compact and frequency band-notch antenna for Ultra-Wideband(UWB) applications is proposed. The designed antenna not only shows good impedance bandwidth for ultra-wideband but has band notch characteristic for the frequency band of $5.15\~5.825\;GHz$ limited by IEEE 802.1la and HIPERLAN/2. To achieve both properties of wide band and band notch, the techniques of a concaved ground plane and inserted U-shaped thin slot into planar radiator are used respectively. A manufactured antenna satisfied VSWR<2 for the frequency band of $2.95\~11.7\GHz$ except the limited band of $4.92\~5.866\;GHz$.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.4
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• pp.1-8
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• 2011

In this paper, a microstrip bandpass filter(BPF) with 3 dB bandwidth of more than 50 % at center frequency of 30 GHz was implemented. The implemented BPF is to be used as ASK(Amplitude Shift Keying) transmission and reception filters in IF band for THz transmitter and receiver capable of 10 Gb/s wireless data transmission. The microstrip BPF with ultra-wideband characteristics was implemented using a stepped-impedance lowpass filter(LPF) and a composite quarter-wave short stubs where the LPF is functioning as attenuating the upper stopband and quarter-wave short stubs is functioning as attenuating the lower stopband. The measured results are as follows; the insertion loss is 0.65 dB at 30 GHz, the stopband characteristics are -10 dB and -16 dB at 10 GHz and 50 GHz, respectively, and the passband flatness is ${\pm}0.5$ dB at 20~40 GHz.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1666-1667
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• 2011

본 논문에서는 CSRR을 이용하여 0.5~1.5GHz 대역의 광대역 필터를 최적 설계 연구 하였다. Metamaterial의 일종인 CSRR은 LC 공진기 역할을 하며 전송선로와 결합하여 필터 특성을 나타낸다. 또한 높은 Q-factor의 특성을 갖기 때문에 협대역 대역통과 필터 특성을 갖는다. 이에 본 논문에서는 CSRR을 이용하여 광대역 대역통과 특성을 갑기 위해서 전송선로의 형태를 변형하고 진화알고리즘중 하나인 진화 전략기법을 이용하여 단일 셀의 최적 설계를 수행하였다. 이후 단위 셀을 다단으로 연결하여 최종 광대역 필터를 설계하였다. 본 논문에서 설계된 광대역 필터는 0.5~1.5GHz의 대역폭을 갖으며 00~00dB의 삽입손실을 갖는다. 그리고 저지대역에서 00~00dB의 저지 특성을 갖는다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.2
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• pp.124-128
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• 2009

This raper proposes a dual-bandstop filter, which is based on a metamaterial transmission line using the composite right/left-handed (CRLH) and dual composite right/left-handed (D-CRLH) structures. The metamaterial structure is used for miniaturization and dual-bandstop operation at the TDMB frequency range (195 MHz) and DVB-T/H frequency range (670 MHz). The size of the proposed filter is $30{\times}15\;mm$, and the -10 dB bandstop fractional bandwidth is approximately 73 % and 50 % at each frequency, respectively.