• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.22 no.1
• /
• pp.9-15
• /
• 2011

In this paper, we designed and fabricated a dual-band bandpass filter which can control upper and lower bandwidth using the transformed E-shaped dual-mode resonator. The filter is made the coupling between even-mode not to affect odd-mode resonant frequency by the transformed resonator to control upper bandwidth effectively. The cross coupling between input and output feed lines was employed to improve stopband characteristic. The bandpass filter has been designed to indicate the same bandwidth at center frequency 2 GHz and 3 GHz to show to control bandwidth.

• The Journal of the Korea Contents Association
• /
• v.7 no.7
• /
• pp.24-30
• /
• 2007

This paper observed characteristics of a triangular microstrip patch antenna with T-slot. When a narrow horizontal slot or vertical slot is embedded in a triangular microstrip antenna, we investigated variations of dual resonant frequency according to slot lengths and then we could make a triangular microstrip antenna with T-type slot suitable to a very low dielectric substrate. The proposed antennas used a dielectric substrate which has relative dielectric constant ${\epsilon}_r=3.38$ and a height of 8 [mils] (=0.2032mm) and antenna characteristics of horizontal or vertical slot antennas are compared by a ensemble 8.0 simulator. Theoretical and experimental results of manufactured antennas are compared.

• Proceedings of the KIPE Conference
• /
• 2003.07b
• /
• pp.491-494
• /
• 2003

This paper presents a new conceptual electromagnetic induction eddy current-based stainless steel plate spiral type heater for heat exchanger or Dual Packs Heater in hot water producer, boiler steamer and super heated steamer, which is more suitable and acceptable for new generation consumer power applications. In addition, all active clamped edge resonant PWM high frequency inverter using trench gate IGBTs power module can operate under a principle oi zero voltage soft communication with PWM is developed and demonstrated for a high efficient Induction heated hot water producer and boiler in the consumer power applications. This consumer induction heater power appliance using active clamp soft switching PWM high frequency inverter is evaluated and discussed on the basis of the simulation and experimental results.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.20 no.2
• /
• pp.23-31
• /
• 2021

Surface texturing is a promising route to reduce the friction forces between two surfaces in sliding contact. To this end, the fabrication of micro dimples is one of the most widely used surface texturing methods. According to published results, textured surfaces with elliptical micro dimples offer the best friction performance. Therefore, we fabricated elliptical micro dimples on carbon steel (SM45C) by using dual frequency vibration assisted machining. High and low frequencies of 16.3 kHz and 230 Hz were applied to the 3D resonant elliptical vibrator. The 3D resonant elliptical vibrator with a triangular cubic boron nitride insert was assembled on a computer numerically controlled turning lathe. Oval micro dimples of various profiles were manufactured on carbon steel. In terms of the profile of the elliptical micro dimples, the experimental results indicated that the average micro dimple width and depth were 112 ㎛ and 7.7 ㎛. These dimensions are closely related to the cutting conditions and can be easily controlled.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.21 no.12
• /
• pp.1447-1453
• /
• 2010

In this paper, the design and the fabrication of dual-band bandpass filter using two dual-mode resonators is presented. Dual-mode resonator using a short stub is miniaturized by inter-digital capacitor and stepped impedance. Two dual mode resonators are designed to have different resonant frequencies, one for the lower passband and the other for the upper passband. Transmission zero is positioned at low or high rejection bands with a sharp skirt characteristic. Dual-band operation can be achieved using dual feeding structure. For WLAN, the proposed filter at 2.45/5.25 GHz is designed and fabricated. The size of the filter is as compact as 1$10.83\;mm{\times}5.3\;mm$.

• Journal of Power Electronics
• /
• v.14 no.6
• /
• pp.1224-1232
• /
• 2014

A full-bridge secondary dual-resonant DC-DC converter using the asymmetrical pulse-width modulated (APWM) strategy is proposed in this paper. The proposed converter achieves zero-voltage switching for the power switches and zero-current switching for the rectifier diodes in the whole load range without the help of any auxiliary circuit. Given the use of the APWM strategy, a circulating current that exists in a traditional phase-shift full-bridge converter is eliminated. The voltage stress of secondary rectifier diodes in the proposed converter is also clamped to the output voltage. Thus, the existing voltage oscillation of diodes in traditional PSFB converters is eliminated. This paper presents the circuit configuration of the proposed converter and analyzes its operating principle. Experimental results of a 1 kW 385 V/48 V prototype are presented to verify the analysis results of the proposed converter.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.179-185
• /
• 2005

This paper presents a novel circuit topology of a high efficiency single-phase power conditioner. This power conditioner is composed of time-sharing sinewave absolute pulse width modulated boost chopper with a bypass diode in the first power processing stage and time-sharing sinewave pulse width modulated full-bridge inverter in the second power processing stage operated by time-sharing dual mode pulse pattern control scheme. The unique operating principle of the two power processing stage with time-sharing dual mode sinewave modulation scheme is described with a design example. This paper proposes also a sinewave tracking voltage controlled soft switching PWM boost chopper with a passive auxiliary edge-resonant snubber. The new conceptual operating principle of this novel power conditioner related to new energy utilization system is presented and discussed through the experimental results.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2001.05a
• /
• pp.337-340
• /
• 2001

In this paper, we propose two types of dual-mode voltage controlled oscillators (VCO) for PCS/IMT-2000 applications. One is a VCO with controllable resonant circuit. The other type is a VCO with single output and two independent parts

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.5 no.2
• /
• pp.321-325
• /
• 2001

In this paper, we propose two types of dual-mode voltage cont.oiled oscillators (VCO) for PCS/IMT-2000 applications. One is a VCO with controllable resonant circuit. The other type is a VCO with single output and two independent parts.

• ETRI Journal
• /
• v.32 no.4
• /
• pp.614-617
• /
• 2010

For an antenna-in-package (AiP), via holes are used to connect the antenna ground and system ground. In this letter, a dual-frequency AiP with a U-slot embedded in the patch is proposed. By properly arranging three via holes under the non-radiating edge, an AiP with two resonant frequencies is realized. Then a U-slot is embedded in the patch to further improve the bandwidth of the AiP. To validate the proposed design, an AiP with the bandwidth of 4.49% at 2.45 GHz and 6.02% at 5.32 GHz is achieved and fabricated. The measured results agree with the simulated results.