• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.1
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• pp.8-14
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• 2016

In this paper, a compact CPW-fed antenna for 5 GHz (5.15-5.35 GHz, 5.725-5.825 GHz) band WLAN applications is presented. The designed antenna's shape is step structure. The antenna is fabricated and measured into FR-4 substrate of dielectric comstant 4.2 and thickness 1.0 mm with optimized parameters obtained by simulation. We confirm that it is operated as antenna for WLAN applications by obtaining the measured return loss level of < -10 dB in 5.133-5.982 GHz. The dimensions of the antenna ($20.0{\times}16.0{\times}1.0mm^3$) shows an compactness of about 67.17% with respect to a conventional folded slot antenna.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.2
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• pp.75-79
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• 2015

In this paper, a dual band antenna with the operating frequency in HF and UHF band was proposed. The antenna structure consists of three spiral turns coil in the bottom side to generate the HF frequency of 13.56 MHz. In the top of the antenna, an inverted-spiral dipole structure is used to create the UHF frequency of 922 MHz. The dual band antenna was optimized to reduce size with $80mm{\times}40mm{\times}0.8mm$ dimension. The antenna presents the omnidirectional characteristic with high gain. To validate the theoretical design, the antenna was simulated using FR-4 substrate and verified the simulation results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.1
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• pp.81-88
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• 2011

This paper presents a design of spiral antenna with broad bandwidth for non-linear junction detector(NLJD). An elliptical patch as radiating element located on center position of radiating surface, as well as the spiral elements on radiating surface was designed for broad bandwidth of spiral antenna. An antenna ground structure generating the multi resonance by spiral slit inserted on ground surface was also proposed. In order to realize high directivity and high gain of the proposed antenna, the cavity wall made of Fr4-epoxy and the metal cap were considered in design. As a result, the calculated gain of antenna with metal cap was improved about 3 dB with comparison of antenna without metal cap and the measured main beam directivity toward -z axis direction agreed well with calculation result. The measured axial ratio satisfied the circular polarization within -z axis ${\pm}45^{\circ}$ at design frequency bands and showed reasonable agreement with prediction.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.5
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• pp.528-537
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• 2011

In this paper, a broadband antenna of the CPW structure with a band-notched characteristic is presented. To obtain this characteristic, the complementary split ring resonator(CSRR) is inserted in the ground plane. In addition, the IEEE 802.11a WLAN band(5.15～5.825 GHz) appears in the band-notched characteristic. The proposed antenna dimension is $36{\times}60{\times}1.6\;mm^3$, and it is designed on the FR-4 substrate having a relative dielectric constant of 4.4. The designed antenna shows that the resonant frequency is 2.03～10.78 GHz below the return loss of -10 dB and a VSWR less than 2 was satisfied. As a result, the proposed CSRR has a band-notched characteristic in the range of 4.917～6.017 GHz which the center frequency is about 5.4 GHz band.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.71-72
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• 2013

In this paper, a design method for a compact slot antenna for 5.8 GHz RFID band (5.725-5.875 GHz) is studied. The proposed slot antenna is size-reduced by bending both ends of the straight slot in "${\Gamma}$"-shape, and a rectangular feed patch is located inside the slot. The effects of slot length, location of feed patch, and width and length of feed patch on the antenna performance are examined. A prototype antenna with optimized parameters for 5.8 GHz band is fabricated on an FR4 substrate and tested experimentally. The experimental results show that the frequency band for a VSWR < 3 ranges 5.72-6.13 GHz (bandwidth 410 MHz), and it corresponds fairly well with the simulated band 5.64-5.97 GHz (bandwidth 330 MHz). The fabricated antenna shows good radiation performance such as maximum power density in both directions normal to the slot plane, and low cross-polarization level of < -20 dB.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.1
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• pp.19-25
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• 2015

In this paper, a design method for a CPW-fed slot antenna for harmonic suppression is studied. The structure of the proposed slot antenna is a rectangular slot antenna appended with stepped impedance resonators (SIRs) at both ends of the slot symmetrically. Optimal design parameters are obtained by analyzing the effects of the length and width of the SIRs on the input reflection coefficient. The optimized harmonic-suppressed slot antenna operating at 2.45 GHz WLAN band is fabricated on an FR4 substrate with a dimension of 42 mm by 30 mm. The slot length of the proposed harmonic-suppressed slot antenna is reduced to 33.3% compared to that of a conventional rectangular slot antenna owing to the appended SIRs. Experiment results show that the antenna has a desired impedance characteristic with a frequency band of 2.39-2.49 GHz for a VSWR < 2, and a measured gain of 2.5 dBi at 2.45 GHz.

• Journal of IKEEE
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• v.24 no.4
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• pp.1028-1033
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• 2020

The existing in-band interference reduction method recommends the physical separation distance between wireless devices and interference signals, and the interference can be suppressed through the separation distance. If the in-band interference signals can be reduced in a wireless device, a margin can be given to the physical separation distance. Since there is an effect of extending the receiver dynamic range of receivers, it is highly useful for interference reduction and improvement method. In this paper, the structure of an in-band analog IRM(Interference Reduction Module) is proposed and the design and implementation of the proposed analog IRM are described. To design an analog IRM, the interference reduction performance according to the delay mismatch, phase error and the number of delay lines that affect the performance of the analog IRM was simulated. The proposed analog IRM composed of 16 delay lines was implemented and the implemented IRM has the interference reduction performance of about 10dB for a 5G(NR-FR1-TM-1.1) signal having a 40MHz bandwidth at a center frequency of 3.32GHz. The analog IRM proposed in this paper can be used as an in-band interference canceller.

• Journal of Technologic Dentistry
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• v.36 no.4
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• pp.231-237
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• 2014

Purpose: This study was performed fracture strength test by conducted change of abutment and coping shape for suggesting monolithic all ceramic crown which has thin thickness and superior strength of the occlusal surface. Methods: The specimens on the four kinds abutment was made according to thickness of occlusal surface and angle of axis surface. And All ceramic coping specimens of 6 different kinds was made by the CAD/CAM Method. Compression strength test using the UTM and the verification of compression-stress situation using the 3D finite element method were conducted under optimum conditions. Results: 516C specimen was showed the strongest compression-fracture strength, followed by 516FR, 516F45, specimens. Did not show significant differences between 516FR and 516F45. 516C of the universal testing machine the specimen's surface that are within the vertical load is small, finite element method of a uniformly distributed load, so the value received suggests otherwise. Conclusion: In conclusion, abutments of monolithic ziconia ceramic when having a same thickness of the occlusal, as the angle of occlusal edge is small, the stress is well dispersed and it can endure well in the fracture.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.7A
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• pp.678-682
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• 2011

In this paper, a compact log periodic dipole array (LPDA) antenna operating from 1 to 6 GHz is studied. Inverted-L shaped dipole elements are used to miniaturize the lateral size of an LPDA antenna and the spacing factor is also decreased to reduce the total length of the LPDA antenna. As the top-loading length of the inverted-L shaped dipole elements is increased, the width of the LPDA antenna is decreased but the bandwidth and the gain of the antenna are decreased. The fabricated compact LPDA antenna is printed on FR4 substrate With a dielectric constant of 4.4 and a thickness of 1.6 mm, and its size is reduced to 32% in width and 49% in length compared to a standard LPDA antenna.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.3
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• pp.44-44
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• 2001

본 논문에서는 CMOS로 구현된 3.3V 8-bit 200MSPS의 Folding / Interpolation 구조의 A/D 변환기를 제안한다. 회로에 사용된 구조는 FR(Folding Rate)이 8, NFB(Number of Folding Block)가 4, Interpolation rate 이 8이며, 분산 Track and Hold 구조를 회로를 사용하여 Sampling시 입력주파수를 Hold하여 높은 SNDR을 얻을 수 있었다. 고속동작과 저 전력 기능을 위하여 향상된 래치와 디지털 Encoder를 제안하였고 지연시간 보정을 위한 회로도 제안하였다. 제안된 ADC는 0.35㎛, 2-Poly, 3-Metal, n-well CMOS 공정을 사용하여 제작되었으며, 유효 칩 면적은 1070㎛×650㎛ 이고, 3.3V전압에서 230mW의 전력소모를 나타내었다. 입력 주파수 10MHz, 샘플링 주파수 200MHz에서의 INL과 DNL은 ±1LSB 이내로 측정되었으며, SNDR은 43㏈로 측정되었다.