• Journal of Power Electronics
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• 제15권5호
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• pp.1409-1420
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• 2015

In this paper, an algorithm using two bi-quad filters to suppress the wide-band resonance for PMSM servo systems is proposed. This algorithm is based on the double bi-quad filters structure, so it is named, "double bi-quad filter." The conventional single bi-quad filter method cannot suppress unexpected mechanical terms, which may lead to oscillations on the load side. A double bi-quad filter structure, which can cancel the effects of compliant coupling and suppress wide-band resonance, is realized by inserting a virtual filter after the motor speed output. In practical implementation, the proposed control structure is composed of two bi-quad filters on both the forward and feedback paths of the speed control loop. Both of them collectively complete the wide-band resonance suppression, and the filter on the feedback path can solve the oscillation on the load side. Meanwhile, with this approach, in certain cases, the servo system can be more robust than with the single bi-quad filter method. A step by step design procedure is provided for the proposed algorithm. Finally, its advantages are verified by theoretical analysis and experimental results.

• 한국군사과학기술학회지
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• 제17권1호
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• pp.57-63
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• 2014

In this paper, we have proposed a wide band antenna for manpack SDR(Software Defined Radio). The proposed antenna consists of feeding post, flexible gooseneck and two radiating elements composed of a upper and lower radiators. The upper radiator has a longer electrical length than the lower radiator in order to operate in the lower frequency. Also, the resonant frequency and impedance characteristics of the antenna can be adjusted independently for two radiators. Therefore, the proposed antenna can be achieved wide impedance bandwidth by the combination of two independent resonance modes. To analyze the characteristics of the antenna in the design process is employed the equivalent circuit theory and EM(Electro-Magnetic) simulation. The measurement results show that the proposed antenna have the sufficient wide bandwidth, above -3.4dBi of the gain and fairly good radiation pattern over the wide bandwidth.

• 한국자기공명학회:학술대회논문집
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• 한국자기공명학회 1999년도 동계총회 및 제14회 자기공명 학술발표회
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• pp.8-8
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• 1999

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2009년도 정보통신설비 학술대회
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• pp.215-218
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• 2009

In this paper, Dual-band bandpass filter studied design using Parallel Coupled SIR(Stepped Impedance Resonator). This Dual-band bandpass filter design SIR of half-wavelength by Parallel-coupled type that is available to RFID system and Changed structure in Meander form by size reduce. Because seen Dual-band bandpass filter is designed so that is applicable for frequency 433MHz and 2.45GHz of RFID system is very wide distance between two pass-band, establish 433MHz by fundamental frequency and controlled 2.45GHz by 2st spurious resonance frequency bandstop filter of 1st spurious resonance frequency and Parallel coupled SIR Combine to remove 1st spurious resonance frequency.

• 전기학회논문지
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• 제60권2호
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• pp.431-434
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• 2011

In this paper, bandwidth enhanced design of dielectric resonator antenna fabricated in multi-layer substrate is introduced. The proposed dielectric resonator antenna is operating with fundamental TE101 mode and higher-order TM111 mode. Each resonance frequency is dependent on resonator dimensions. As increasing the height of radiating aperture, the higher-order TM111 mode resonance frequency approach the fundamental TE101 mode resonance frequency and the antenna bandwidth increase by double resonance. Three different aperture height size antennas that operated at 7GHz are fabricated in FR4 multi-layer substrate. Measured 10 dB matching bandwidth is 8 percent for single resonace antenna and 18 percent for double resonance antenna.

• Journal of electromagnetic engineering and science
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• 제18권1호
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• pp.46-51
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• 2018

In this paper, a planar printed hybrid short/open-ended slot antenna with capacitive coupling feed strips is proposed for hepta-band mobile applications. The proposed antenna is comprised of a slotted ground plane on the top plane and two capacitive coupling feed strips with a chip inductor on the bottom plane. At the low frequency band, the short-ended long slot fed by strip 1 generates its half-wavelength resonance mode, whereas the T-shaped open ended slot fed by strip 2 generates its quarter-wavelength resonance mode for the high frequency band. The antenna provides a wide bandwidth covering GSM850/GSM900/DCS/PCS/UMTS/LTE2300/LTE2500 operation bands. Moreover, the antenna occupies a small volume of $15mm{\times}50mm{\times}1mm$. The operating principle of the proposed antenna and the simulation/measurement results are presented and discussed.

• 한국전자파학회논문지
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• 제29권10호
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• pp.817-820
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• 2018

본 논문에서는 스마트 안경에서 사용가능한 2.4 GHz 무선 근거리 통신망(WLAN) 대역용 소형 다중 입력 다중 출력(MIMO) 안테나 설계 및 구현에 대한 제안을 하였다. MIMO 안테나 시스템을 소형화하기 위해서, 안테나의 그라운드면을 방사체로서 사용하였으며, T 자형의 접지면을 제안하고 있다. 광대역 격리를 특성을 확보하기 위해, 이중 공진이 그라운드 모드에서 형성되도록 한다. 하나의 공진은 T 자형 접지에 의해 생성되고, 두 번째 공진은 두 개의 급전선 사이에 슬롯과 커패시터를 추가하여 만들어진다. 구현된 안테나의 측정 결과, 반사 계수 특성은 -5.1 dB보다 작지만, 얻는 격리 특성은 -20 dB 미만이다. 다이버시티 성능은 측정된 2차원 방사 패턴을 사용하여 평가하였고, 목표 대역(2.4~2.5 GHz)에서 측정된 ECC(envelope correlation coefficients) 값은 0.1 미만이다.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
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• pp.524-527
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• 2003

In this paper, a new design for a Coplanar Waveguide (CPW) fed wide-band slot antenna is presented. To enhance the impedance bandwidth of the slot antenna, we proposed the tapering slot structure. A various resonance modes are generated in the tapering slot. The impedance bandwidth of the proposed antenna is about 12:1 ($2.0GHz{\sim}24.3GHz$) with $VSWR{\le}2$. Simulation results for return loss and radiation pattern are presented.

• 한국전자파학회논문지
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• 제15권2호
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• pp.212-216
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• 2004

본 논문에서는 새로운 구조의 CPW 급전 광대역 슬롯 안테나를 제안하였다. 안테나의 슬롯 구조를 비대칭 곡선형 테이퍼 형태로 구현하여 다중 공진 모드를 형성시킴으로써 임피던스 대역폭을 확장시키는 효과를 가져왔다. 제안된 안테나의 측정된 임피던스 대역폭(VSWR$\leq$2)은 약 13:1(2.0 GHz∼25.9 GHz)을 나타내었다. 이는 기존의 CPW 급전 슬롯 안테나의 임피던스 대역폭을 크게 개선한 것이며 모의실험 및 측정된 반사손실과 복사 패턴을 표현하였다.

• 한국전자파학회논문지
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• 제18권4호
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• pp.358-363
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• 2007

본 논문에서는 휴대 방송용 기기에 적합한 다중 대역 및 광대역 안테나를 제안한다. 제안된 안테나는 두 복사체의 공진 주파수를 인접시킴으로써 DVB-H 서비스 대역에서의 광대역 특성을 만족시키고, 체배 주파수를 이용하여 DAB 서비스 대역에서 동작 가능케 한다. 3개의 공진 주파수 조정함에 있어서 상호 영향이 적기 때문에 비교적 쉽게 대역폭을 만족시킬 수 있다. 제작된 안테나는 DVB-H 서비스 대역인 $470{\sim}740\;MHz$와 DAB 서비스 대역인 $1,450{\sim}1,480\;MHz$ 대역에서 VSWR 2:1 이하의 특성을 가지며, 각각 $1.97{\sim}4.10\;dBi$와 $1.98{\sim}2.04\;dBi$의 최대 이득 특성을 갖는다.