• Journal of electromagnetic engineering and science
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• 제5권4호
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• pp.208-212
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• 2005

In this paper, we introduced a band-pass filter employed the PBG structure and the aperture on the ground together. The harmonics of band pass filter have been suppressed by employing the PBG structure and the bandwidth of it has been broadened by using the aperture on the ground. The designed PBG cells have three different sizes. The largest cells, the middle cells, and the smallest cells have suppressed the multiple of second harmonics, the multiple of third harmonics, and the multiple of fifth harmonics, respectively. The center frequency has been 2.18 GHz. The bandwidth has been increased from 230 MHz up to 310 MHz(80 MHz, about $35\%$) by the aperture and the ripple characteristics in passband have been improved and the harmonic frequencies have been suppressed about 30 dB by the PBG.

• ETRI Journal
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• 제29권4호
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• pp.533-535
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• 2007

For the purpose of decreasing intermodulation distortion, a new multi-harmonic suppression band-pass filter based on a microstrip radial stub is studied. Compared with traditional resonator filters, the new filter can suppress the second, third, and even fourth harmonics directly. The dimension of the filter is about $0.3\;{\lambda}_{g^0}{\times}0.13\;{\lambda}_{g^0}$ (${\lambda}_{g^0}$ is the guiding wavelength at the resonant frequency). Only one gap was introduced, so lower insertion loss can be obtained. Basic agreement between the measured and simulated results has been achieved.

• 전자공학회논문지
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• 제51권1호
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• pp.42-46
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• 2014

고조파를 제거하는 기능을 갖는 윌킨슨 전력분배기를 나타내었다. 종래의 윌킨슨 전력분배기에서 선로 변환기의 양단에 제거할 고조파의 수만큼의 전송선로를 추가한 후에 새로운 윌킨슨 전력분배기의 해를 구할 수 있다. 실험적인 결과는 기본 주파수에서는 종래의 기능을 유지하면서 2차 및 3차 고조파를 -45.3 dB 및 -37 dB의 억압비를 나타내었다.

• 한국전자파학회논문지
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• 제17권9호
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• pp.845-851
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• 2006

본 논문에서는 접힌 구조를 이용하여 소형화되고 고조파 특성이 개선된 링-하이브리드를 설계하였다. 제안한 구조는 링-하이브리드의 링 구조를 LPF 특성을 갖는 접힌 구조의 결합 선로를 이용하여 구성함으로써 링의 크기 감소뿐만 아니라 고조파 제거 특성도 부가하였다. 중심 주파수 2.41 GHz에서 일반적인 링-하이브리드와 같은 특성이 같고 3차 고조파를 포함한 11 GHz까지 -20 dB 이하의 저지 특성을 가지고 있다. 또한 링의 크기가 기존의 1/4 크기로 줄어들었다. 제작된 링-하이브리드의 측정된 주파수 특성 결과는 회로 및 EM 시뮬레이션 결과와 잘 일치한다.

• 한국전자파학회논문지
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• 제29권3호
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• pp.151-158
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• 2018

본 논문에서는 4~6 %의 협대역 필터를 구현함에 있어서 광대역으로 고조파 성분을 억제하기 위하여 suspended-strip 선로 상에 2개의 헤어핀 계단형 임피던스 공진기 구조를 구현한 새로운 설계법을 제시하였다. 제안된 협대역 필터의 구현의 예로, 중심주파수 $f_0=1.4GHz$에서 5 %의 대역폭의 협대역 필터를 구현하였고, $7.5f_0$까지 광대역 고조파 억제 대역을 구현할 수 있음을 보였다. 이 결과는 기존 마이크로스트립 선로를 사용한 협대역 필터 설계법에 비해 2배 이상 넓은 고조파 억제가 구현 가능함을 입증한 것이며, 삽입손실 또한 0.9 dB로 우수한 특성을 얻었다.

• 한국항해항만학회지
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• 제29권7호
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• pp.615-618
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• 2005

A new structure of the Wilkinson power divider that can suppress multiple harmonics output is presented The power divider consists of T-type or $\pi$-type capacitive loads and shunt resistors. Experimental results show that this power divider suppresses the second and the third harmonic components to less than -38dB, while maintaining the characteristics of a conventional Wilkinson power divider, featuring an equal power split, a simultaneous impedance matching at all ports and a good isolation between output ports.

• ETRI Journal
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• 제28권4호
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• pp.529-532
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• 2006

This letter describes a compact printed helical resonator and its application to a microwave oscillator circuit implemented in coplanar waveguide (CPW) technology. The high quality (Q)-factor and spurious-free characteristic of the resonator contribute to the phase noise reduction and the harmonic suppression of the resulting oscillator circuit, respectively. The designed resonator showed a loaded Q-factor of 180 in a chip area of only 40% of the corresponding miniaturized hairpin resonator without any spurious resonances. The fully planar oscillator incorporated with this resonator showed an additional phase noise reduction of 10.5 dB at a 1 MHz offset and a second harmonic suppression enhancement of 6 dB when compared to those of a conventional CPW oscillator without the planar helical resonator structure.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2009년도 정보통신설비 학술대회
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• pp.293-297
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• 2009

In this thesis, design of a VCO(Voltage controlled Oscillator) with a novel tuning mechanism is presented for the Radar system. This circuit, the 9.5 GHz oscillator is designed and implemented by restructuring microstrip resonator to raise Q value and to require a wide frequency tuning range. This product is fabricated on 2.6 Teflon substrate and device is NE722S01. In this paper, The new microstrip resonator VCO is proposed to achieve the characteristic of a wide frequency tuning range. This microstrip resonator VCO shows the phase noise characteristic of -108.3 dBc/Hz at 1 MHz offset from the fundamental frequency, the output power of 5.7 dBm and the second harmonic suppression of -38 dBc for the VCO are obtained. The manufacture VCO shows a frequency tuning range of 193.8 MHz. The proposed micro trip resonator VCO can be used for X-band Radar System with required tuning range.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
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• pp.145-149
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• 2003

The parallel feedback dielectric resonator oscillator (DRO) which is applicable to satellite communications and broadcasting has been investigated. In the design of oscillator, the phase noise is important parameter. In this paper, The proposed oscillator has good phase noise level because it suppressed harmonics. Measurement show the fabricated oscillator is output power of about 9 dBm at fundamental frequency of 12.0 GHz and fundamental frequency suppression of -47.5 dBc. The phase noise level is about -110 dBc/Hz at 100 KHz offset frequency.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 통신소사이어티 추계학술대회논문집
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• pp.72-76
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• 2003

In this paper, active frequency doubler with broadband characteristics and unconditional stability from 6GHz to 12GHz was designed and fabricated using PHEMT. The designed frequency multiplier has a bias point near pinch-off and a proposed RC circuit between bias line and input matching network for the improvement of stability. With 0dBm input power, second harmonic of 1.7dBm at 12GHz, - 27.5dBc suppression of 6GHz fundamental, -18dBc suppression of 18GHz 3rd harmonic and the output bandwidth of 1.8GHz have been measured.