• 한국전자파학회논문지
• /
• 제24권6호
• /
• pp.581-585
• /
• 2013

마이크로스트립 패치 안테나의 대역폭을 확장하기 위한 방안을 제시하였다. 이 안테나는 사각형의 슬롯을 가진 접지판 위에 변형된 T-자 모양의 마이크로스트립 라인으로 급전되는 구조를 갖는다. 제시된 마이크로스트 립 패치 안테나는 슬롯과 변형된 T-자 모양의 급전 라인의 크기와 위치를 최적화시킴으로써 광대역 특성을 구현 하였다. 컴퓨터 모의실험 결과에 의하면 VSWR 2:1 기준에서 127.8 %(0.65~2.95 GHz)의 대역폭을 얻을 수 있었다.

• 한국기계가공학회지
• /
• 제21권5호
• /
• pp.61-66
• /
• 2022

This study investigated the characteristics and relationship between surface roughness and vibration according to the cutting conditions in the slot milling of AL7075-T6. The spindle speed, feed, and depth of cut were selected as independent variables and the amplitude of acceleration and surface roughness as dependent variables. Feed affected the surface roughness. As the spindle speed increased, the amplitude of vibration increased in the direction perpendicular to the feed direction. In addition, the amplitude of vibration and surface roughness showed a negative correlation. Under a given feed, the surface roughness improved as the vibration increased.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제11권3호
• /
• pp.1492-1509
• /
• 2017

The wireless sensor network (WSN) is a key technology to support the Internet of things (IoT) paradigm. The efficiency of the MAC protocol in WSN is very important to take scalability with restricted wireless resources. The DESYNC-TDMA has an advantage of simple distributed slot allocation inspired by nature, but there is a critical disadvantage of split slots by firing message. The basic split slot model has less efficiency for continuous packet transmitting because of wasting of the slots less than the packet size. In this paper, we propose a firing offset adjustment scheme to improve the efficiency of slot utilizations, which can manage the slot assigned to each node as a single large block, called the single slot model. The performance analysis models for both the existing and the proposed schemes are also derived. Experimental results show that the proposed method provide better efficiency of slot utilization than the existing schemes without any loss of the nature of the desynchronization.

• 한국전자파학회논문지
• /
• 제12권4호
• /
• pp.562-569
• /
• 2001

본 논문은 T-모양 급전선을 갖는 마이크로스트립 슬롯 안테나의 최적 설계방법에 대하여 연구하였다. T-모양의 급전선을 갖는 마이크로스트립 슬롯안테나의 대역폭에 가장 큰 영향을 주는 설계변수는 급전선의 offset 위치로 가로 방향의 급전선 길이로서, 기판의 유전상수와 두께 그리고 슬롯 폭이 주어지면 설계한 안테나가 최대 대역촉을 갖도록 두 설계변수를 계산할 수 있는 식을 curve fitting을 통하여 유도하였다. 시뮬레이션하여 최대 대역폭을 갖도록 최적화 시킨 안테나의 offset 위치와 급전선 가로길이를 이식을 이용하여 계산한 값과 각각 비교하였고 그 결과가 잘 일치하였다.

• 대한치과교정학회지
• /
• 제45권1호
• /
• pp.29-37
• /
• 2015

Objective: The coefficients of friction (COFs) of aesthetic ceramic and stainless steel brackets used in conjunction with stainless steel archwires were investigated using a modified linear tribometer and special computer software, and the effects of the bracket slot size (0.018 inches [in] or 0.022 in) and materials (ceramic or metal) on the COF were determined. Methods: Four types of ceramic (one with a stainless steel slot) and one conventional stainless steel bracket were tested with two types of archwire sizes: a $0.017{\times}0.025$-in wire in the 0.018-in slots and a $0.019{\times}0.025$-in wire in the 0.022-in slot brackets. For pairwise comparisons between the 0.018-in and 0.022-in slot sizes in the same bracket, an independent sample t-test was used. One-way and two-way analysis of variance (ANOVA) and Tukey's post-hoc test at the 95% confidence level (${\alpha}$ = 0.05) were also used for statistical analyses. Results: There were significant differences between the 0.022-in and 0.018-in slot sizes for the same brand of bracket. ANOVA also showed that both slot size and bracket slot material had significant effects on COF values (p < 0.001). The ceramic bracket with a 0.022-in stainless steel slot showed the lowest mean COF (${\mu}$ = 0.18), followed by the conventional stainless steel bracket with a 0.022-in slot (${\mu}$ = 0.21). The monocrystalline alumina ceramic bracket with a 0.018-in slot had the highest COF (${\mu}$ = 0.85). Conclusions: Brackets with stainless steel slots exhibit lower COFs than ceramic slot brackets. All brackets show lower COFs as the slot size increases.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 1999년도 추계종합학술대회 논문집
• /
• pp.147-150
• /
• 1999

A T-shaped microstripline-fed printed slot array antenna having wide bandwidth, high gain, and narrow bandwidth is presented in this paper. The proposed antenna is analyzed by using the transmission line model method. We fabricated 4$\times$1 microstrip slot array antenna and measured its return loss and radiation pattern. The maximum bandwidth of this array antenna is from 1.43 ㎓ to 2.60 ㎓, which is 58.1% for the VSWR $\leq$ 2.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2004년도 ICCAS
• /
• pp.211-214
• /
• 2004

Microstrip slot array antenna fed by microstrip line is introduced. Slot antenna is designed to operate at 10 GHz for using in radar systems. Antenna have dielectric constant of the substrate is 2.17 (PTFE). In fact, it is study to analyze slot array antenna including feeding line with wide bandwidth. The characteristics of antenna is proposed and analyzed for instance input impedance, $S_{11}$ parameter and far field radiation patterns which these characteristics can also be calculated efficiently and accurately by using FDTD Method.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제54권7호
• /
• pp.323-328
• /
• 2005

This paper is proposed maximum thrust design of slotted permanent magnet linear synchronous motor(PMLSM) using surface harmonic method(SHM) considering slot effect. The genetic a1gorithm is used for optimization. The functional are selected the maximum thrust and the minimum detent force. This time. design parameters are set as permanent magnet(PM) width. PM height and slot width. Thrust is increased from 272[N] to 295[N] and detent force is decreased from 5[N] to 2.43[N] greatly in optimum design. Therefore, thrust ripple isn't generating almost. Also, the results of 2D EMC considering slot-effect are compared with ones of experimental and finite element analysis..

• Journal of electromagnetic engineering and science
• /
• 제18권1호
• /
• pp.46-51
• /
• 2018

In this paper, a planar printed hybrid short/open-ended slot antenna with capacitive coupling feed strips is proposed for hepta-band mobile applications. The proposed antenna is comprised of a slotted ground plane on the top plane and two capacitive coupling feed strips with a chip inductor on the bottom plane. At the low frequency band, the short-ended long slot fed by strip 1 generates its half-wavelength resonance mode, whereas the T-shaped open ended slot fed by strip 2 generates its quarter-wavelength resonance mode for the high frequency band. The antenna provides a wide bandwidth covering GSM850/GSM900/DCS/PCS/UMTS/LTE2300/LTE2500 operation bands. Moreover, the antenna occupies a small volume of $15mm{\times}50mm{\times}1mm$. The operating principle of the proposed antenna and the simulation/measurement results are presented and discussed.

• 대한전자공학회논문지TE
• /
• 제37권2호
• /
• pp.69-74
• /
• 2000

T-모양의 마이크로스트립 급전 구조를 갖는 슬롯 안테나는 정합을 쉽게 이룰 수 있고 대역폭이 기존의 급전 구조의 슬롯 안테나에 비하여 넓었다. 양방향으로 복사체를 갖는 슬롯 안테나가 한 방향으로만 복사하기를 원할 경우, 반사판을 별도로 설치해야 한다. 그러나 본 논문에서 제시한 한 방향으로만 복사체를 갖는 슬롯 안테나는 반사판 설치가 필요 없게 된다. 그래서 반사판을 포함하는 2-층의 유전체 층에 십자형 급전구조를 갖는 마이크로스트립 슬롯 복사체인 새로운 방법을 제시하였다. FDTD 법으로 해석하여 전계분포를 시간 영역에서 계산하였고, 이를 Fourier 변환시켜 슬롯 안테나의 반사손실, 전압 정재파비, 복사패턴을 주파수 영역에서 계산하였다. 그리고 슬롯의 길이(I/sub s/)와 폭(W/sub s/), 수평부 급전선의 길이(I/sub d/), 상측 수직 급전선의 길이(l/sub u/), offset 에 따라 대역폭이 민감하게 변한다. 설계변수들을 최적화한 후에 측정한 결과, 최대 대역폭은 중심 주파수 2.5㎓에서 1,850㎒의 광대역 특성을 얻었다.