• Title, Summary, Keyword: Slot

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Triangular Microstrip Antenna with T-type Slot (T형 Slot을 삽입한 삼각형 안테나)

  • Park, Byoung-Woo;Shin, Hye-Jung
    • The Journal of the Korea Contents Association
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    • v.7 no.7
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    • pp.24-30
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    • 2007
  • This paper observed characteristics of a triangular microstrip patch antenna with T-slot. When a narrow horizontal slot or vertical slot is embedded in a triangular microstrip antenna, we investigated variations of dual resonant frequency according to slot lengths and then we could make a triangular microstrip antenna with T-type slot suitable to a very low dielectric substrate. The proposed antennas used a dielectric substrate which has relative dielectric constant ${\epsilon}_r=3.38$ and a height of 8 [mils] (=0.2032mm) and antenna characteristics of horizontal or vertical slot antennas are compared by a ensemble 8.0 simulator. Theoretical and experimental results of manufactured antennas are compared.

Design and Fabrication of a Broadband Microstrip Slot Antenna with a Fork-shaped Feedline (포크모양의 급전선로를 갖는 광대역 마이크로스트립 슬롯 안테나 설계 및 제작)

  • 문영길;김흥수
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.41 no.8
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    • pp.87-92
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    • 2004
  • In this paper, a microstrip slot antenna with a fork-shaped feedline is designed and fabricated. To obtain a broadband characteristic of a wide slot antenna a feedline is transformed into a shape of a fork, and a size of the slot and offset - length is varied. As the characteristics of the slot antenna as the function of design parameters are analyzed, a broadband microstrip slot antenna is designed. The microstrip slot antenna with a fork-shaped feedline is fabricated and its measured bandwidth is from 1.65 GHz to 6.20 GHz for VSWR$\leq$2.

Design a Non-Slot Step Folded PIFA and Analyze the Characteristic for Dual-Band GSM and W-CDMA

  • Lee, Vea-O;Ko, Hyun-Jung;Park, Sang-Bok;Cheon, Chang-Yul;Jeong, Yong-Seek
    • 한국정보통신설비학회:학술대회논문집
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    • pp.3-6
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    • 2008
  • In this paper, we propose the folded PIFA with its made an alteration to a factor of resonance for L-slot PIFA. Proposed antenna maintain diminished size patch and improve each bandwidth of GSM(0.88$\sim$-0.96 GHz) and W-CDMA(1.92$\sim$2,17 GHz) for miniaturized repeater. The non-slot step folded PIFA's structure that design of essence was general L-slot PIFA for dual-band. It has no U-slot, multi band and the another slot. The parameters of proposed antenna were optimized for dual-band and compact size by folded singleness patch. Proposed antenna by using folded singleness patch take satisfaction main point, bandwidth of GSM and W-CDMA, compact patch size($39{\times}21{\times}13mm^3$). The antenna was designed by FDTD simulation tool and it was made from result of simulation. Measured data shown that the proposed non-slot step folded PIFA was strong possibility.

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Design of a Multiple Band-notched Wideband Circular Slot Antenna with Arc-shaped Slots

  • Yeo, Junho;Park, Cheol-Young
    • Journal of the Korea Industrial Information Systems Research
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    • v.18 no.1
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    • pp.11-17
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    • 2013
  • A design method to achieve multiple band-rejection characteristics in a wideband circular slot antenna is presented. First, a wideband circular slot antenna fed by a coplanar waveguide is designed to operate in the frequency range between 2.3 and 11GHz, which covers WLAN, WiBro, WiMAX, and UWB frequency bands. Next, resonant frequency variations of rejection bands are examined with respect to different slot locations and lengths when slots are inserted on the ground conductor and the circular patch of the antenna. When arc-shaped slots are placed close to the circular transition from a feeding part, multiple notch bands are obtained. In this case, a half of the guided wavelength of the first notch band corresponds to the slot length and other notch bands are integer-multiple of the first band. Single notch band can be obtained when the slot is located off the transition part. Based on this study, a wideband circular slot antenna with five band-rejection frequency bands at 2.45, 3.5, 4.9, 7.35, and 9.8GHz is designed and fabricated. The first arc-shaped slots are located in the ground conductor close to the circular transition from a feeding part to generate notch bands at 2.45, 4.9, 7.35, and 9.8GHz, while the second slot for 3.73 GHz is placed on top side in the circular patch. The proposed design method is validated by good agreement between the simulated and measured results.

A Novel Skewed-Type Iron Slot Wedge for Permanent Magnet Synchronous Generators for Improving Output Power and Reducing Cogging Torque

  • Kang, Sun-Il;Moon, Jae-Won;You, Yong-Min;Lee, Jin-Hee;Kwon, Byung-Il
    • Journal of Electrical Engineering and Technology
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    • v.10 no.1
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    • pp.243-250
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    • 2015
  • This paper proposes a novel skewed-type iron slot wedge that can improve both the cogging torque and the output power of a permanent magnet synchronous generator (PMSG). Generally the open slot structure is adopted in a PMSG due to its convenient winding work, but the high cogging torque is undesired. Firstly, an iron slot wedge was utilized to reduce the cogging torque of an open slot type PMSG. However, the output power of the machine decreased rapidly with this method. Thus, a proposed skewed type iron slot wedge is presented to improve the output power as well as the cogging torque as compared to the open slot type. Shape optimization of the skewed-type iron slot wedge is performed to simultaneously maximize the output power and reduce the cogging torque. The Kriging model based on the Halton sequence method and a genetic algorithm are used to optimize the design.

Performance Enhancement of Slot-Count Selection Algorithm with Weight Differentiation in Gen-2 RFID Systems (Gen-2 RFID 시스템에서 가중치 차별화를 통한 슬롯 카운트 선택 알고리즘의 성능 향상)

  • Lim, In-Taek
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.15 no.3
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    • pp.561-566
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    • 2011
  • In EPCglobal Class-1 Gen-2 RFID system, a slot-count selection algorithm has been proposed to determine the slot-count size depending on the status of reply slot. In the slot-count selection algorithm of Gen-2, the slot-count value is increased or decreased by the weight C, which is identical and independent of the slot status. It has an advantage that the algorithm is simple, but it is difficult to maintain an optimal slot-count size. Therefore, in this paper, we propose an adaptive slot-count selection algorithm, which applies the parameter C differently based on the result of tag replies. Through simulations, it is demonstrated that the collision rate for the proposed scheme is about 42% and 65% lower than the schemes proposed by Wang and Gen-2. Therefore, the adaptive slot-count selection algorithm achieves faster tag identification time compared with the existing algorithms due to the low collision rate.

Numerical and Experimental Study on the Surge Performance Improvement by the Bleed Slot Casing of a Centrifugal Compressor (서지성능 향상을 위한 원심압축기의 Bleed Slot Casing의 설계변수에 대한 해석 및 시험 평가)

  • Kim, Hong-Won;Chung, Jae-Hoon;Ryu, Seung-Hyup;Lee, Geun Sik
    • The KSFM Journal of Fluid Machinery
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    • v.18 no.2
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    • pp.22-28
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    • 2015
  • The primary design goal of a compressor is focused on improving efficiency. Secondary objective is to widen the operating range of compressor. This paper presents a numerical and experimental investigation of the influence of the bleed slot on the operating range for the 1.2 MW class centrifugal compressor installed in a turbocharger. The main design parameters of the bleed slot casing are upstream slot position, inlet pipe slope, downstream slot position and width. The DOE(design of experiment) method was carried out to optimize the casing design. Numerical analyses were done by the commercial code ANSYS-CFX based on the three dimensional Reynolds-averaged Navier-Stokes equations. Results showed that efficiency and pressure ratio increased as the downstream slot position and width were smaller and the upstream position was located away from the impeller inlet. Experimental works were also done with and without the bleed slot casing. The simulation results were in good agreement with the test data. Enhancement of both the surge margin up to 26.5% and the pressure ratio with the optimized bleed slot design were achieved, compared with the surge margin of only 6.6% without the bleed slot casing.

Non-Offset Longitudinal Shunt Slot Exited by an Asymmetry Compound Iris (비대칭 복합 아이리스에 의해 여기되는 비이격 종방향 션트슬롯)

  • Kim, Byung-Mun;Hong, Jae-Pyo;Cho, Young-Ki
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.27 no.8
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    • pp.684-692
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    • 2016
  • In this paper, a non-offset longitudinal shunt slot excited by an asymmetry compound iris on the broad wall of a rectangular waveguide is presented as an element for a waveguide slot-array antenna(WSAA). By properly adjusting the iris dimension, a resonance of the slot at a desired frequency can be achieved. The proposed resonant slot has some advantageous properties, such as a wide range of normalized resonant conductance, and minimum change of phase in the waveguide at the resonance. In addition, when the slots are arrayed for a waveguide slot antenna, the unwanted cross-polarization level can be reduced because each slot is placed in a straight line. A $8{\times}1$ WSAA with -20 dB side-lobe level(SLL) is designed, fabricated, and tested experimentally. The measured results are well agreed with the simulated ones and have an SLL of -18.13 dB and a cross-polarization level of -48.85 dB at 9.41 GHz, which was improved by about 15 dB of that of the conventional longitudinal slot array antenna.

Evaluations of Swaging Process for Rotor Core of Induction Motors (유도전동기 회전자 제작시 압입작업 평가)

  • Park, Sang-Chul
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.10
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    • pp.21-26
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    • 2016
  • This study evaluates the magnitudes and distributions of contact tangential forces with the swaging depth of punch acting at the contact surfaces between a rotor core slot and a Cu bar during a sequential rotor core swaging process. The effects of the core slot shape on the magnitudes and distributions of the total contact forces were investigated to improve the productivity of the rotor core swaging process. Parametric elastic-plastic numerical analyses were performed using simplified two-dimensional cyclic symmetric plane strain models to evaluate the contact force distributions at the contact surfaces. The numerical analysis results show that the total contact tangential forces increased by about 55% with the adjacent Cu bar swaging process. The length of the core slot is a dominant factor in the core slot design as result of the increased total contact tangential forces during the swaging process of the rotor core.

Compact Dual-band Slot Antenna With Bent Slots (접힌 슬롯이 추가된 소형 이중 대역 슬롯 안테나)

  • Baek, Woon-Seok
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.20 no.6
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    • pp.1049-1056
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    • 2016
  • In this paper, a design method for a compact dual-band slot antenna with bent slot is studied. Bent slots are added on the rectangular slot of the proposed antenna for dual-band operation. The rectangular slot is fed by a coaxial cable by placing a rectangular feeding patch inside the slot. When the bent slots are added onto the both corner of the upper side of the rectangular slot symmetrically, a new resonant frequency is created in low frequency because of the increasement of the slot length. A prototype of the proposed dual-band slot antenna operating at 2.45 GHz WLAN band and 4.50-8.30 GHz band including 5GHz WLAN 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 2.40-2.49 GHz and 4.33-9.85 GHz for an input reflection coefficient < -10 dB.