• Title, Summary, Keyword: U-type slot

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Design of A Dual-resonance PIFA Using U-Type Slot (U-형 슬랏을 이용한 이중 공진 PIFA 설계)

  • Kim, Yoon-Ho;Rhee, Joong-Geun;Kim, Jung-Hun;Jang, Tae-Heon
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.47 no.11
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    • pp.77-83
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    • 2010
  • This paper presents the dual resonance PIFA(Planar Inverted F-Antenna) which satisfies the requirements of the 802.11n standard at both 2.4 GHz and 5 GHz frequency bands. Patch for 2.4 GHz and U-Type slot for 5 GHz were used for dual resonance, respectively. In this paper, the characteristics of an antenna were investigated by varying locations of short plate and feed point, the width of the short plate, the thickness and the location of U-Type slot. To investigate the characteristics of the PIFA, HFSS(High Frequency Structure Simulation) for the simulation was used. And the measurement results of a fabricated PIFA were compared with the simulated ones. The measurement and simulation results show that good dual resonance characteristics as the thickness of U-type slot decreases and when the location of U-type slot is far from the feed point.

A Broadband Characteristic of Wide Slot Planar Antenna By CPW-Fed (CPW급전에 의한 폭넓은 평면 슬롯안테나의 광대역특성)

  • Lee, Hyeon-Jin;Seo, Jang-Soo
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.58 no.4
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    • pp.374-376
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    • 2009
  • In this paper, a CPW fed and inversed U-type monopole structure wide slot antenna for novel broadband calacturictics 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 2.3 GHz(3.85~6.15 GHz) at 10 dB and the simulated antenna gain is about 6 dBi at 5.4 GHz.

A Study On The Stator Slot Shape Design of BLDC Motor (BLDC 모터 고정자 슬롯 형상설계에 관한 연구)

  • Han, Sang-Rog;Lee, Kang-Yeon;Jeong, Byeong-Ho
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.29 no.5
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    • pp.41-49
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    • 2015
  • In this paper, we studied an optimal design and efficiency improvement of the BLCD motor used in home electronic appliance. The number of stator slots is chosen depending on the rotor poles, phase number, and the winding configuration. In general, a fractional slots/pole design is preferred to minimize cogging torque. To reduce the winding resistance, we reduced the coil length and we improved the coil space factor. We proposed three types of stator slot shape design for the optimal BLDC motor design. One of them, U-type slot shape is a best optimal design, it proved by the simulated and tested. Optimal design of essential parameters aiming at high winding factor are presented to create for a high-quality system implementation. Design analysis is verified by testing and building a prototype motor.

Directivity Gain Improvement Method for UWB Coplanar Patch Antenna (UWB 평면 패치안테나의 지향성이득의 향상 방법)

  • Joo, Chang-Bok
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.49 no.6
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    • pp.63-70
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    • 2012
  • This paper discussed on the directive gain improvement method of the U-type ultra wide-band(UWB) planar patch antenna model with CPW feeding. For directive gain improvement, the U-type printed patch antenna model with CPW feeding is reconstructed as a microstrip structure by adding a reflection plane with aperture slot. The reflection coefficient of the reconstructed antenna is less than -6.5 dB(VSWR < 3.3) to the characteristic impedance of $50.08{\Omega}$ and showed the directive radiation patterns with the directive gain of 7.5 dBi ~ 10.1 dBi, the front-back ratio of 17.8 dB ~ 28.7 dB and the range of -3dB radiation angle over ${\pm}30^{\circ}$ to the main beam direction of ${\theta}=0^{\circ}$.

A Study on an Optimal Design of a Triple-band PIFA using the Evolution Strategy (진화 알고리즘을 이용한 삼중대역 PIFA 최적 설계에 관한 연구)

  • Ko, Jae-Hyeong;Kim, Koon-Tae;Kim, Kyong-Ah;Kim, Hyeong-Seok
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.4
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    • pp.768-773
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    • 2010
  • In this paper, we study on an optimal design of a triple-band PIFA (Planar Inverted-F Antenna) of 433 MHz, 912 MHz and 2.45 GHz by using evolution strategy. Generally, the resonant frequency of the PIFA is determined by the width and length of a U-type slot used. However the resonant frequencies of the multiple U slots are varied by the mutual effect of the slots. Thus the optimal width and length of U-type slots are determined by using an optimal design program based on the evolution strategy. To achieve this, an interface program between a commercial EM analysis tool and the optimal design program is constructed for implementing the evolution strategy technique that seeks a global optimum of the objective function through the iterative design process consisting of variation and reproduction. The resonant frequencies of initial model are 439.5 MHz, 981.5 MHz and 2.563 GHz. However, the resonant frequencies of the triple-band PIFA yielded by the optimal design program are 430.5 MHz, 907 MHz and 2.4515 GHz. Measured resonant frequencies are 433.5 MHz, 905.5 MHz and 2.454GHz, which show a good agreement with the simulation results.

Design of Square Patch Reflectarray Antenna with U-type Slot (U자형 슬롯을 갖는 정사각형 패치 리플렉트어레이 안테나의 설계)

  • Kim, Seon-Hye;Choi, Hak-Keun;Park, Jae-Hyun
    • The Journal of The Institute of Internet, Broadcasting and Communication
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    • v.11 no.3
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    • pp.9-15
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    • 2011
  • The microstrip reflectarray antenna is rapidly becoming an attractive alternative solution to the traditional parabolic reflector antenna. However, the bandwidth of the microstrip reflectarray using the single layer structure is very narrow. To obtain wide bandwidth characteristic, the microstrip reflectarray using the multi-layer structure has been used, but it has some disadvantages such as high cost and complicated design. In this paper, to obtain low cost and wide bandwidth, the microstrip reflectarray antenna composed of square patch with two U-slots using the single-layer structure is proposed. The proposed antenna demonstrate radiation efficiency closed to 55.5 % and 1 dB gain bandwidth over 14 % at 12.5 GHz.

A Design of a Planar UWB Antenna with Notched WLAN band by Using Slot and Slit (슬롯과 슬릿을 사용하여 무선랜 대역이 제거된 평면형 UWB안테나 설계)

  • Lee, Chang-Joo;Kim, Su-Hoon;Park, Young-Bon;Lee, Mun-Soo
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.49 no.6
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    • pp.105-110
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    • 2012
  • In this paper, A planar UWB antenna with notched WLAN band, 802.11a band (5.15 ~ 5.825GHz), by using slot and slit is designed by using CST Microwave Studio. The notched bandwidth can be controlled by the length and width of the slot and slit in the patch and ground plane and it's radiation characteristics are examined through the experiments. The bandwidth based on the -10dB return loss level can be covered the full UWB band (3.1 ~ 10.6GHz) with a notched WLAN band (5.147 ~ 5.83GHz). Also, the experimental radiation pattern is almost omnidirectional in the H-plane.

Impact on Retrievability by Cement Variety for Implant Restorations Equipped with a Lingual Slot

  • Lee, Ji-Hong;Lee, Kyu-Bok
    • Journal of Korean Dental Science
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    • v.11 no.1
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    • pp.14-20
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    • 2018
  • Purpose: The purpose of this study is to measure and compare the removal torques of different cements applied in attachments of zirconia restorations on titanium (Ti) abutments fitted with retrievable cement-type slot (RCS) on the lingual side for the better retrievablity by use of a slot driver. Materials and Methods: Three types of cements were used in the experiment: two permanent cements in $RelyX^{TM}$ U200 (RU) (3M ESPE) which is a resin cement and $FujiCem^{TM}$ (FC) (GC) which is a resin-modified glass ionomer cement, and a temporary cement in $Freegenol^{TM}$ temporary cement (TC) (GC). Measurements of removal torques were conducted as follows; an attached sample was fixed on the equipment customized for the experiment; a slot driver was connected to a MGT12 (Mark-10 Corp.), a torque measurement instrument; the sample had the driver fitted to its RCS and then was rotated until the it was removed; and finally, the maximum torque value was recorded. Result: As for the removal torque measurement results, the average values were $47.9{\pm}2.6Ncm$ for RU, $43.4{\pm}1.5Ncm$ for FC, and $20.9{\pm}1.0Ncm$ for TC. The statistical analysis using Kruskal-Wallis test yielded the significance probability of P<0.05 (P=0.002), which confirmed the presence of significant differences between the three groups. Conclusion: All three cements exhibit clinically acceptable levels of removal torque when applied to an upper zirconia implant restoration fitted with a lingual slot, with RU and FC, the two permanent cements, having the significantly higher values than that of TC, the temporary cement.

Comparision of the characteristics of 3-phase squirrel cage induction motor with slit and U-iron bridge type rotor slot (회전자 슬롯에 U자형 Iron bridge와 Slit이 있는 3상 농형 유도전동기의 특성비교)

  • Kim, B.T.;Kwon, B.I.;Park, S.C.;Kim, K.W.;Yoon, J.H.
    • Proceedings of the KIEE Conference
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    • pp.41-43
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    • 1997
  • This paper represents the comparison of harmonic loss characteristics of the inverter-driven 3-phase squirrel cage induction motor with slit and U-iron bridge slots of rotor. Two-dimensional time-stepped finite element method is used for electromagenetic field analysis. And spectrums of bar current, phase current, and torque are compared in each case.

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Influence of abutment height and convergence angle on the retrievability of cement-retained implant prostheses with a lingual slot

  • Choi, Kyu-Hyung;Son, KeunBaDa;Lee, Du-Hyeong;Lee, Kyu-Bok
    • The Journal of Advanced Prosthodontics
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    • v.10 no.5
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    • pp.381-387
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    • 2018
  • PURPOSE. Cement-retained implant prostheses can lack proper retrievability during repair, and residual cement can cause peri-implantitis. The purpose of this in vitro study was to evaluate the influence of abutment height and convergence angle on the retrievability of cement-retained implant prostheses with lingual slots, known as retrievable cement-type slots (RCS). MATERIALS AND METHODS. We fabricated six types of titanium abutments (10 of each type) with two different heights (4 mm and 6 mm), three different convergence angles ($8^{\circ}$, $10^{\circ}$, and $12^{\circ}$), a sloped shoulder margin (0.6 mm depth), a rectangular shape ($6mm{\times}6.5mm$) with rounded edges, and a rectangular ledge ($2mm{\times}1mm$) for the RCS. One monolithic zirconia crown was fabricated for each abutment using a dental computer-aided design/computer-aided manufacturing system. The abutments and crowns were permanently cemented together with dual-curing resin cement, followed by 24 hours in demineralized water at room temperature. Using a custom-made device with a slot driver and torque gauge, we recorded the torque ($N{\cdot}cm$) required to remove the crowns. Statistical analysis was conducted using multiple regression analysis and Mann-Whitney U tests (${\alpha}=.05$). RESULTS. Removal torques significantly decreased as convergence angles increased. Multiple regression analysis showed no significant interaction between the abutment height and the convergence angle (Durbin-Watson ratio: 2.186). CONCLUSION. Within the limitations of this in vitro study, we suggest that the retrievability of cement-retained implant prostheses with RCS can be maintained by adjusting the abutment height and convergence angle, even when they are permanently cemented together.