• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.48 no.3
• /
• pp.68-73
• /
• 2011

In this paper, a compact-narrow open stub band-pass filter with parasitic-signal of low frequency range and second harmonics rejected using the parallel coupled line and FLCLM(Frquency Locked Controlled Length Method) is proposed. The characteristic of the parallel coupled line can be rejection for parasitic-signal of low frequency range and second harmonics. In last filter of experimental results show that insertion loss is 1.2 dB and return loss is 14.8 dB, and the fractional bandwidth is 10 % at the center frequency of 5.8 GHz. In additional, the rejection for parasitic-signal of low frequency range and second harmonics are 28.9 dB and 28.8 dB, respectively.

• ETRI Journal
• /
• v.38 no.1
• /
• pp.133-140
• /
• 2016

This paper presents a method of parasitic inductance reduction for high-speed switching and high-efficiency operation of a cascode structure with a low-voltage enhancement-mode silicon (Si) metal-oxide-semiconductor field-effect transistor (MOSFET) and a high-voltage depletion-mode gallium nitride (GaN) fielde-ffect transistor (FET). The method is proposed to add a bonding wire interconnected between the source electrode of the Si MOSFET and the gate electrode of the GaN FET in a conventional cascode structure package to reduce the most critical inductance, which provides the major switching loss for a high switching speed and high efficiency. From the measured results of the proposed and conventional GaN cascode FETs, the rising and falling times of the proposed GaN cascode FET were up to 3.4% and 8.0% faster than those of the conventional GaN cascode FET, respectively, under measurement conditions of 30 V and 5 A. During the rising and falling times, the energy losses of the proposed GaN cascode FET were up to 0.3% and 6.7% lower than those of the conventional GaN cascode FET, respectively.

• Journal of Korea Society of Industrial Information Systems
• /
• v.4 no.4
• /
• pp.111-116
• /
• 1999

In this paper, the electromagnetically coupled microstrip dipole antenna by adapting one parasitic metal-strip(dipole) between the microstrip transmission line open end and the radiating microstrip dipole antenna is presented for the bandwidth improvement The microstrip dipole antenna is simulated using Ensemble 51 simulation package The effects of varying several physical parameters, such as the lengths of radiating dipole and parasitic dipole and the width of parasitic dipole are investigated The bandwidth behavior of the 3-layer optimum antenna is compared with that of 2-layer antenna without the parasitic dipole. Experimental result for the obtained broadband performance is presented and discussed.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.33A no.2
• /
• pp.148-162
• /
• 1996

Bonding wires for high frequency device packaging have dominant parasitic inductances which limit the performance of semiconductor lasers. In this paper, the inductance sof bonding wires are claculated by the method of moments with incorporation of ohmic loss, and the wideband modulation characteristics are analyzed for ddifferent wire lengths and structures. We observed the modulation bandwidth for 1mm-length bonding wire lengths and structures. We observed the modulation bandwidth for 1mm-length bonding wire is 7 GHz wider than that for 2mm-length bonding wire. We also observed th estatic inductance calculation results in dispersive deviation of the parasitic inductance and the modulation characteristics from the wideband moment methods calculations. The angled bonding wire has much less parasitic inductance and improves the modulation bandwidth more than 6 GHz. This calculation resutls an be widely used for designing and packaging of high-speed semiconductor device.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.28A no.12
• /
• pp.12-17
• /
• 1991

In this paper, E-plane gap-coupled rectangular microstrip antennas with parasitic elements are analyzed. The mutual coupling between the radiating edges is represented as the voltage-dependent current source. The gap coupling between the patch and parasitic element is characterized with the REC(Radiating Edges-Coupling) model, and the conventional transmission line model is used to obtain the equivalent circuit of the antenna. The return loss of the rectangular microstrip antennas with short-and open-circuit parasitic elements are calculated and compared with the measured values. The theoretical values including the mutual coupling are more in agreement with the measured values than the calculated values without the mutual coupling.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.19 no.12
• /
• pp.1410-1415
• /
• 2008

This paper proposes an small electronically steerable parasitic array radiator composed of a uniplanar dipole as a feeding element and two dipoles as parasitic elements. The fabricated antenna shows by measurement the $3.3{\sim}4.3\;dB$ gain between $-100{\sim}1000$ azimuth range in the dipole vertical plane and -10 dB return loss within $5.4{\sim}5.9\;GHz$, which includes $5.725{\sim}5.825\;GHz$ UNII band.

• Journal of Korea Society of Industrial Information Systems
• /
• v.15 no.2
• /
• pp.11-16
• /
• 2010

In this papar, we have proposed a small electronically steerable parasitic array radiator with 180 degree azimuth beam coverage and high gain characteristics. The proposed antenna is composed of a uniplanar Yagi dipole as a feeding element and two dipoles as parasitic elements. The fabricated antenna is tested by electronically changing the reactance loaded on the parasitic dipoles and the results show that it has 5.2dB~6.7dB gain in $-90^{\circ}{\sim}90^{\circ}$wide azimuth range and -10dB return loss characteristics within 5.725GHz~5.825GHz UNII band.

• Journal of the Microelectronics and Packaging Society
• /
• v.31 no.3
• /
• pp.99-104
• /
• 2024

With the advancement of power electronics technology and the increasing demand for high-efficiency power semiconductors, silicon carbide (SiC) devices have gained attention as an alternative to overcome the limitations of traditional silicon (Si) semiconductors. SiC devices enable excellent switching efficiency due to their high switching speed. However, parasitic inductance within the power module can cause voltage oscillations and overshoot phenomena, potentially leading to issues with electrical reliability and efficiency. To address these challenges, two approaches were proposed and validated. The first approach involved applying an RC snubber circuit to mitigate the effects of parasitic inductance, thereby improving electrical stability. The second approach focused on optimizing the lead-frame design to reduce parasitic inductance. Both methods were verified through simulations and experiments, demonstrating that the electrical reliability and efficiency of SiC power modules can be simultaneously improved.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.22 no.1
• /
• pp.70-78
• /
• 1998

The present study has tested semi-empirical loss models for a reliable performance prediction of mixed-flow pumps with four different specific speeds. In order to improve the predictive capabilities, this paper recommends a new internal loss model and a modified parasitic loss model. The prediction method presented here is also compared with that based on two-dimensional cascade theory. Predicted performance curves by the proposed set of loss models agree fairly well with experimental data for a variety of mixed-flow pumps in the normal operating range, but further studies considering 'droop-like' head performance characteristic due to flow reversal in mixed-flow impellers at low flow range near shut-off head are needed.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.21 no.6
• /
• pp.804-812
• /
• 1997

The present study has tested most of loss models previously published in the open literature and found an optimum set of empirical loss models for a reliable performance prediction of centrifugal compressors. In order to improve the prediction of efficiency curves, this paper recommends a modified parasitic loss model. Predicted performance curves by the proposed optimum set agree fairly well with experimental data for a variety of centrifugal compressors. The prediction method developed through this study can serve as a tool for preliminary design and assist the understanding of the operational characteristics of general purpose centrifugal compressors.