• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.6 no.2
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• pp.27-34
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• 1995

In this paper, an X-band TDRO(transistor dielectric resonator oscillator) is designed and experimented with the oscillator constructed. Design of the TDRO is carried out by deriving analycally the coupling parameters between a microstrip line and a dielectric resonator. The coupling parameters take account of the relations among substrate material, ground plane, metallic boundaries surrounding the resonator, distance between a microstrip line and a resonator. Two criteria, external quality factor and coupling coefficient, have been chosen in order to evaluate the performance of the TDRO designed. TDRO studed in this paper may be useful for the application of a microwave system requiring a stable and effective oscillator frequency.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.7
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• pp.633-640
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• 2002

In this paper, the small chip meander antenna for dual-frequency operation is presented. The proposed chip meander antennas was fabricated by the ceramic chip using LTCC-MLC process. It is a novel compact dual-frequency design using a meandered patch that achieves more degrees of freedom for adjusting dual-frequency operation and the size reduction with narrow frequency ratio. And it is proposed that the 3D structure for additional size reduction of the meander antenna. The size reduction of the 3D meander antenna is as large as 50 % as compared to the design for dual-frequency operation not using 3D structure. It is observed that the principle of dual-frequency operation through current distribution, return loss and radiation pattern.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.10
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• pp.1115-1121
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• 2008

In this paper, dielectric slab loaded cylindrical cavity resonator measurement technique is presented to determine the dielectric constant of a dielectric material. The dielectric constant is measured by the resonant frequency deviation of empty and dielectric slab loaded cavity. Characteristic equations are derived by th exact field analysis. The measurement configurations are formed using HP8719A vector network analyzer and an experimental cylindrical metallic cavity with circular cross-section. The validity of the theory is confirmed by experiments and CST MWS 4.0(3D simulator). The results were in the whole satisfactory. The measured dielectric constant of teflon and bakelite are 2.03 and 4.44, respectively.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.28-29
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• 2017

기존의 위상천이 풀 브리지 DC/DC 컨버터의 경우 변압기의 누설 인덕턴스와 2차 측 정류 다이오드의 기생 출력 커패시턴스 사이의 공진으로 인하여 정류 다이오드 양단에 큰 공진 전압이 발생하며, 이는 소자의 신뢰성 저하 및 시스템의 전력 변환 효율을 감소시킨다. 반면 LLC 공진형 컨버터는 2차 측에서 발생되는 공진 에너지가 출력 커패시터로 흡수되지만 경 부하시에 높은 스위칭 주파수로 인하여 효율이 저감되며, 출력 전압을 제어하기 위해 추가적인 부하저항이 요구된다. 따라서 최근에는 LLC 공진형 컨버터로 동작시키면서도 PWM 제어를 통해 출력전압을 제어하는 방법이 연구되고 있으나, 새로운 게이트 구동 방식을 위해 DSP 제어를 사용하고 있다. 따라서 본 논문에서는 산업에서 많이 사용되고 있는 아날로그 IC를 통해 동일한 동작 및 성능을 구현시킬 수 있는 방법에 대하여 제안한다. 본 논문에서는 제안된 방식의 타당성을 검증하기 위하여 이론적으로 분석하며, 6.6kW급 시작품을 제작하여 제안방식의 타당성을 검증하였다.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.127-129
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• 2019

본 논문은 Solid-state Marx modulator (SSMM)용 10 kV, 1 kW급 고전압 커패시터 충전기의 설계에 대해 기술한다. 개발된 Marx modulator용 충전기는 소프트 스위칭방식을 통해 높은 스위칭 주파수로 동작하는 컨버터를 제안함으로써 고밀도 설계를 구현한다. 특히 고전압 변압기 설계에 있어 피할 수 없는 누설 인덕턴스와 기생 커패시턴스를 회로의 파라미터로 사용 할 수 있는 공진형 컨버터를 기반으로 설계한다. 본 논문에서는 순수 전류원 특성을 가지며 스위치 온, 오프 시 모두 소프트 스위칭이 가능한 Discontinuous Conduction Mode (DCM) 직렬 공진형 컨버터와 공진 전류의 RMS값을 줄이고 변압기의 기생 커패시턴스를 공진 탱크로 사용하는 LCC 공진형 컨버터 Continuous Conduction Mode (CCM)를 설계한다. 각 컨버터의 동작에 따른 해석 및 공진 파라메터 상세 설계에 대해 기술하고 정격 운전 (10 kV, 1 kW) 실험결과를 통해 각 컨버터 토폴로지의 장단점을 비교하고 최종 실험결과에 대해 기술한다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.9 s.112
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• pp.883-889
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• 2006

In this paper, parasitic resonance modes generated in a conductor backed coplanar wave guide(CBCPW) and stripline band pass filter(BPF) and the oscillation phenomena of a 40 GHz power amplifier module(PAM) are analyzed and several methods to suppress them are presented for low-temperature co-fired ceramic(LTCC) based millimeter-wave RF System-in-Package(SiP) applications. Parasitic rectangular wave guide(RWG) modes of the CBCPW structure are completely suppressed in the operation frequency band by decreasing the distance between its vias and by increasing the mode frequency. In the stripline structure, RWG resonance modes are clearly eliminated by removing some vias facing each other and by placing them diagonally. In the case of the 40 GHz PAM, in order to reduce a cross talk due to radiation that is generated from interconnection discontinuities, high isolation structures such as embedded DC bas lines and CPW signal lines are used and then the oscillated PAM is improved.

• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.3
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• pp.251-259
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• 2009

In this paper, a contactless power supply using half-bridge series resonant converter that achieves ZVS operation of main switches and ZCS operation of secondary side diodes is proposed. Since the proposed contactless power supply using half-bridge series resonant converter operates with lower switching frequency than the resonant frequency, it can achieve ZCS operation of secondary side diodes due to discontinuous resonant current. And it is also possible to control the converter in narrow frequency range and to obtain high voltage gain, which, in turn, offers low turns ratio for the transformer and high efficiency. Based on the theoretical analysis and simulation results, the 3.15W prototype is built and the final experimental results are described.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.5
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• pp.613-623
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• 2012

In this paper, we present an ultra miniaturized voltage tuned oscillator, with HMIC-type amplifier and phase shifter, using LTCC artificial dielectric resonator. ADR which consists of periodic conductor patterns and stacked layers has a smaller size than a dielectric resonator. The design specification of ADR is obtained from the design goal of oscillator. The structure of the ADR with a stacked circular disk type is chosen. The resonance characteristic, physical dimension and stack number are analyzed. For miniaturization of ADRO, the ADR is internally implemented at the upper part of the LTCC substrate and the other circuits, which are amplifier and phase shifter are integrated at the bottom side respectively. The fabricated ADRO has ultra small size of $13{\times}13{\times}3mm^3$ and is a SMT type. The designed ADRO satisfies the open-loop oscillation condition at the design frequency. As a results, the oscillation frequency range is 2.025~2.108 GHz at a tuning voltage of 0~5 V. The phase noise is $-109{\pm}4$ dBc/Hz at 100 kHz offset frequency and the power is $6.8{\pm}0.2$ dBm. The power frequency tuning normalized figure of merit is -30.88 dB.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.3
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• pp.343-354
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• 2012

In this paper, various spiral zeroth-order resonators are proposed for wireless power transmission. Since a zerothorder resonance(ZOR) mode of meta-material transmission lines has the characteristic of an infinite wavelength, its frequency is independent of physical length. Also, to obtain high transmission efficiencies high-Q resonators and strong coupling coefficient between coupled resonators are required. Therefore, the resonators consist of spiral inductor and lumped capacitor to use the ZOR mode and they are optimized via parametric study and circuit analysis for a high-Q resonator design. The optimized resonators are simulated and compared with a conventional spiral resonator and one of them was fabricated and measured. The fabricated one has a dimension of $20cm{\times}20cm{\times}8cm$($0.009{\lambda}_0{\times}0.009_{\lambda}_0{\times}0.004{\lambda}_0$) and the transmission efficiency of 80 % is measured at 13.56 MHz at transmitted distance of 40 cm.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.2
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• pp.355-360
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• 2024

In this paper, in implementing a 4-coil resonant wireless power transmission system, we studied the discharge phenomenon that occurs at the end of the transmitting resonance coil. Resonant wireless power transmission consists of a power supply coil, a transmitting resonance coil, a power receiving resonance coil, and a load coil. The transmitting resonance coil serves to amplify the magnetic field generated from the power supply coil and transmits it to the front receiving resonance coil. When a high current flows through the power supply coil in order to transmit large power, a high voltage is induced at the end of the transmitting resonance coil. It causes line-to-line discharge. Line-to-line discharge phenomenon damages the transmitter case and renders the transmitter unusable. Therefore, in order to eliminate this line-to-line discharge phenomenon, the voltage induced in the transmitting resonance coil that causes line-to-line discharge was analyzed and a solution was proposed.