• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.154-157
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• 1999

Photonic Slot Routing(PSR) is a promising approach to solve the fundamental scalability problem of all-optical packet switched WDM networks. In photonic slot routing, packets destined for the same subnetwork are aggregated to form a photonic slot which is jointly routed as a single unit of information through the network. The relative location of the nodes from bridge may cause to fairness problem in the unidirectional WDM ring network based on PSR. As photonic slots from different subnetworks can originate contentions at the bridge, packets may be dropped and retransmitted. Thus we evaluated the performance of PSR based WDM ring network in the point of fairness for each node and slot contentions at the bridge. Simulation results show that the PSR based WDM ring requires a slot access mechanism to guarantee the transmission fairness and efficient switch architecture to resolve slot contention at the bridge.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.5
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• pp.773-781
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• 2000

We proposed an eccentric annular ring microstrip slot antenna for improving a narrow bandwidth of the conventional annular ring microstip slot antenna. The proposed antenna has an asymmetric slot and a normal microstrip feedline. This antenna is analyzed and optimized by using the finite difference time domain (FDTD) method. The impedance bandwidth of the optimized antenna is more than 1 octave that is much broader than the conventional annular ring microstrip slot antenna for the same size.

• Journal of information and communication convergence engineering
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• v.15 no.4
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• pp.199-204
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• 2017

A compact dual-band half-ring-shaped (HRS) bent slot antenna fed by a coplanar waveguide for wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications is presented. The antenna consists of two HRS slots with different lengths and widths. The two HRS slots are connected through an arc-shaped slit, and the upper HRS slot is bent in order to reduce the size of the antenna. The optimized dual-band HRS bent slot antenna operating in the 2.45 GHz WLAN and 3.5 GHz WiMAX bands is fabricated on an FR4 substrate with dimensions of 30 mm by 30 mm. The slot length of the proposed dual-band slot antenna is reduced by 35%, compared to a conventional dual-band rectangular slot antenna. Experimental results show that the proposed antenna operates in the frequency bands of 2.40-2.49 GHz and 3.39-3.72 GHz for a voltage standing wave ratio of less than 2, and measured gain is larger than 1.4 dBi in the two bands.

• Journal of electromagnetic engineering and science
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• v.14 no.4
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• pp.367-375
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• 2014

In this paper, a novel triple-band circular-ring monopole antenna with a half-circular ring and ground slot for wireless local area network/Worldwide Interoperability of Microwave Access (WLAN/WiMAX) applications is proposed. The proposed antenna consists of one circular ring, a half-circular ring and a rectangular slot in the ground plane. Based on the concept, a prototype of the proposed triple-band antenna was designed, fabricated and tested. The numerical and experiment results demonstrated that the proposed antenna satisfied the -10 dB impedance bandwidth requirement while simultaneously covering the WLAN and WiMAX bands. Furthermore, this paper presents and discusses the 2D radiation patterns and 2D gains according to the results of the experiment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.10
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• pp.115-120
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• 2018

This study examined the cast quality of small-sized induction motor rotors during the die casting process. Numerical analyses with 3-dimensional half models were performed to investigate the filling patterns of aluminum molten metals into a mold after high-speed injections. The following were obtained from numerical analyses and experimental results. First, molten metals started to fill the lower end ring, then moved horizontally to fill the core slot and upper end ring, and finally stopped to fill the rotor core slot. Second, circulation of molten metals occurred at the lower end ring, resulting considerable porosity at the section of lower end ring from the experimental results. Third, further work for obtaining sound quality of rotor core cast is required to develop a new shape of the rotor core cast or improve the die casting conditions.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.61 no.3
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• pp.149-152
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• 2012

In this paper, a wideband monopole antenna with ring loop by modified ground plane is presented. The proposed antenna consist of monopole antenna, ring loop by ground plane. This antenna is fed CPW-fed and wide slot antenna of a novel structure for broadband characteristics is proposed. To enhance the impedance bandwidth of the wide slot antenna, we proposed the wide slot structure with CPW-fed which is combined with four ${\lambda}/2$ rectangular radiation modified monopole and inductively coupled. The measured impedance bandwidth is about 2.5 GHz(3.65~6.15 GHz) then less -10 dB.

• Journal of Sensor Science and Technology
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• v.31 no.2
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• pp.107-114
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• 2022

The effects of ring radius and coupling spacing on the free spectral range (FSR), full width at half maximum (FWHM), quality factor, and sensitivity of single-channel and add-drop channel slot ring resonators were systematically investigated using FIMMPROP and PICWAVE numerical software. The single-channel ring resonator exhibited better characteristics, namely, a wider FSR and narrower FWHM compared with the add-drop structure; thus, it was evaluated to be more suitable for biochemical sensors. The FSR, FWHM, quality factor, and sensitivity for a single channel ring resonator with a radius of 59.4 ㎛ and coupling gap of 0.5 ㎛ were 2.4 nm, 0.087 nm, 17677, and 550 [nm/RIU], respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.11
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• pp.2526-2533
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• 2015

In this paper, a design method for a compact dual-band coplanar waveguide-fed slot antenna using SRR(split-ring resonator) conductor is studied. The SRR conductor is loaded inside a rectangular slot of the proposed antenna for dual-band operation. When the SRR conductor is inserted into the slot, the original rectangular slot is divided into a rectangular loop region and a rectangular slot region, and frequency bands are created by the loop and slot, separately. A prototype of the proposed dual-band slot antenna operating at 2.45 GHz WLAN band and 3.40-5.35 GHz band is fabricated on an FR4 substrate with a dimension of 30 mm by 30 mm. Experiment results show that the antenna has a desired impedance characteristic with a frequency band of 2.38-2.51 GHz and 3.32-5.38 GHz for a voltage standing wave < 2, and measured gain is 1.7 dBi at 2.45 GHz, and it ranges 2.4-3.2 dBi in the second band.

• Journal of Sensor Science and Technology
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• v.31 no.5
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• pp.353-359
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• 2022

This study investigated via computational analysis the application utility of series-cascaded ring resonators based on silicon-on-insulator (SOI) slot optical waveguides in integrated optical biochemical sensors. The radii of the two rings in the series-cascaded ring resonators were 59.4 ㎛ and 77.6 ㎛ respectively, and the coupling distance was 0.5 ㎛. The series-cascaded ring resonators were computationally analyzed using FIMMProp and PICWave numerical software. The free spectral range (FSR), full width at half maximum (FWHM), sensitivity, and quality-factor (Q-factor) of the series-cascaded ring resonators were 12.2 nm, 0.134 nm, 4100 nm/RIU, and 11580, respectively, and the measurement range was calculated to be slightly smaller than 3×10^-3 RIU. Although the measurement range was smaller than that of the single ring resonator, upon considering other characteristic parameters, the series-cascaded ring resonators are found to be more effective as integrated sensors than single ring resonators.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.347-352
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• 2019

This study focused on improving the cast quality of small-sized induction motor rotors during the die casting process. A new rotor core cast model was proposed based on previous research results and parametric studies. Numerical analyses using 3-dimensional half models were performed to evaluate the filling patterns of aluminum molten metals into a mold and on-site experiment performed to verify the newly proposed cast model. The following were obtained from numerical filling analyses and experimental results. First, molten metals started to fill the lower end ring, then moved on to fill the core slot and upper end ring and finally stopped to fill at the rotor core slot. Second, significant circulation of molten metals was not observed on the lower end ring, resulting in fewer defects at the section of the lower end ring from the experimental results. Third, the new shape of a rotor core cast was effective in producing rotors with sound cast quality, and reducing the end ring cast defect area by approximately 70 %.