• Title, Summary, Keyword: antenna structures

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Design and Fabrication of Composite Smart Structures for Communication (복합재료를 이용한 통신용 지능구조물 설계 및 제작)

  • You, C.S.;Hwang, W.
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.346-349
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    • 2005
  • The present study aims to design electrically and structurally effective antenna structures in order that the structural surface itself could become the antenna. The basic design concept is composite sandwich structure in which microstrip antenna is embedded and this is termed composite smart structure (CSS). The most important outstanding problem is that composite materials of structural function cannot be used without reducing antenna efficiency. Unfortunately, such materials have high electrical loss. This is a significant design problem that needs to be solved in practical applications. Therefore, the effect of composites facesheet on antenna performances is studied in the first stage. Changes in the gain of microstrip antenna due to composites facesheet have been determined. 'Open condition' is defined when gain is maximized and is a significant new concept in the design of high-gain antennas considering bandwidth in practical application. The open condition can be made with any thickness of outer facesheet by controlling its position. In the design of CSS, glass/epoxy composites and Nomex honeycomb were used with exploiting open condition. Experiments, confirm that the gain is improved (over 11 dBi) and the bandwidth is also as wide as specified in our requirements (over 10% at 12.2 GHz). With the open condition, wideband antenna can be integrated with mechanical structures without reducing any electrical performances, as confirmed experimentally here.

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Design and Impact Testing of Cylindrical Composite-Antenna-Structures having High Mechanical Performanc (기계적 특성이 우수한 원통형 복합재료 안테나의 설계 및 충격 실험)

  • Kim, Dong-Seop;Jo, Sang-Hyeon;Hwang, Un-Bong;Lee, Jung-Hui
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.35-38
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    • 2005
  • The Objective of this work was to design Composite Antenna Structures (CAS) and investigate impact behavior of CAS which was various curvature. This term, CAS, indicates that structural surface becomes antenna. Constituent materials were selected considering electrical properties, dielectric constants and tangent loss as well as mechanical properties. For the antenna performance, microstrip antenna layers inserted into structural layers were designed for satellite communication at the resonant frequency of 12.5 GHz and final demonstration article was. After making five kinds of curved CAS, which radii of curvature are flat, 200, 150, 100, 50 mm. The antenna performance changed in accordance with variation of curvature. The Reflection coefficient was independent of curvature but the gain decreased with the radius of curvature. The impact test equipment was Dyna-8250 drop weight tester. The impact characteristic in accordance with curvature is maximum absorb energy is same each other. The impact energy was 8.5 J. For various Impact energy test, five energy levels 3 J, 5 J, 7 J, 10 J, 20 J were used. The performance of impact damaged antenna was estimated by measuring the return loss and the radiation pattern. It was revealed that the performance of antenna was not related to the impact damage. Because the impactor did not damage the patch directly. CAS have good impact stability for the antenna performance.

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Antenna Integration with Composite Sandwich Structure using Transmission/Reflection Methods of Incident Wave (신호의 투과/반사법을 이용한 복합재료 샌드위치 구조 속으로의 안테나 삽입)

  • You, C.S.;Hwang, W.
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.55-58
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    • 2005
  • The present study aims to design electrically and structurally effective antenna structures in order that the structural surface itself could become the antenna. The basic design concept is composite sandwich structure in which microstrip antenna is embedded and this is termed composite smart structure (CSS). The most important outstanding problem is that composite materials of structural function cannot be used without reducing antenna efficiency. Unfortunately, such materials have high electrical loss. This is a significant design problem that needs to be solved in practical applications. Therefore, the effects of composites facesheet on antenna performances are investigated in the first stage and changes in the gain of microstrip antenna due to composites facesheet have been determined. ‘Open condition’ is defined when gain is maximized and is a significant new concept for the design of high-gain antennas considering bandwidth in practical application. The open condition can be made with the outer facesheet by controlling its position. In the design of CSS, glass/epoxy composites and Nomex honeycomb were used with exploiting open condition. Experiments, confirm that the gain is improved and the bandwidth is also as wide as specified in our requirements. With the open condition, wideband antenna can be integrated with mechanical structures without reducing any electrical performances, as confirmed experimentally here.

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Characteristics of Loop Antenna Structure of RFID Tag Antenna

  • Kim, Yeon-Ho;Park, Young-Kwon;Lee, Kyung-Hwan;Kim, Goo-Jo;Chung, You-Chung
    • Proceedings of the Korea Society of Information Technology Applications Conference
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    • pp.353-356
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    • 2005
  • A loop RFID tag antenna and a dipole RFID antenna with a T-matching method have been designed. The characteristic of loop and dipole with T-matching antenna structures of RFID tag antennas have been studied. The impedance of different sizes of loop and dipole antenna structures are found. This paper shows parametric research of loop RFID antenna structure and RFID dipole antenna with T-matching method to match the impedance of commercially available RFID chips.

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Circularly Polarized Electromagnetic Band Gap Patch-Slot Antenna with Circular Offset Slot

  • Hajlaoui, El Amjed
    • Journal of information and communication convergence engineering
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    • v.16 no.3
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    • pp.197-202
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    • 2018
  • This paper reveals the impact of the insertion of electromagnetic band gap (EBG) structures on the performance of circularly polarized (CP) patch-slot antenna with offset slot. Several optimizations are necessary to precise physical parameters in the aim to fix the resonance frequency at 3.2 GHz. The proposed antenna possesses lightweight, simplicity, low cost, and circular polarization ensured by two feeding sources to permit right-hand and left-hand circular polarization process (RHCP and LHCP). The measured results compared with simulation results of the proposed circularly polarized EBG antenna with offset slot show good band operations with –10 dB impedance bandwidths of 9.1% and 36.2% centered at 3.2 GHz, which cover weather radar, surface ship radar, and some communications satellites bands. Our investigation will confirm the simulation and experimental results of the EBG antenna involving new EBG structures.

Design of Microstrip Antenna with Composite Laminates and its structural rigidity (복합재료 평면 안테나 구조의 제작 및 기계적 특성 평가)

  • 전지훈;유치상;김차겸;황운봉;박현철;박위상
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.195-198
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    • 2002
  • Two types of conformal load-bearing antenna structure (CLAS) were designed with microwave composite laminates and Nomex honeycomb cores, to give both structural rigidity and good electrical performance. One is 4$\times$8 array for Synthetic Aperture Radar(SAR) system and the other is $5\times2$ array for wireless LAN system. Design was based on wide bandwidth, high polarization purity, low loss and good structural rigidity. We studied the design, fabrication and structural/electrical performances of the antenna structures. The flexural behavior was observed under a 3-point bending test, an impact test, and a buckling test. Electrical measurements were in good agreement with simulation results and these complex antenna structures have good flexural characteristics. The design of this antenna structure is extended to give a useful guide for sandwich panel manufacturers as well as antenna designers.

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Analysis of Radiation Characteristics of Microstrip Patch Antennas Integrated with Mushroom-like EBG Structures (Mushroom 형태의 EBG 구조를 집적한 마이크로스트립 패치안테나의 방사 특성 해석)

  • Kwak, Eun-Hyuk;Kim, Tae-Young;Kim, Boo-Gyoun
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.46 no.8
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    • pp.67-78
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    • 2009
  • Radiation characteristics of microstrip patch antennas integrated with mushroom-like EBG structures in all directions and length direction on a substrate with the relative dielectric constant of 10 are systematically analyzed. As the substrate thickness increases, the effect of the surface wave on the input impedance and radiation pattern of a patch antenna increases. The effect of EBG structures on the input impedance of a patch antenna is negligible when the distances between EBG structures and the center of a patch antenna are 0.4 ${\gamma}_0$, 0.2 ${\gamma}_0$ and 0.1 ${\gamma}_0$ for the substrate thickness of 3.2 mm, 1.6 mm and 0.8 mm, respectively. The forward radiation is improved due to the suppression of surface wave when the periods of EBG structures integrated are larger than 2, 2, 3 periods for the substrate thickness of 3.2 mm, 1.6 mm and 0.8 mm, respectively. The effects of EBG structures on the radiation characteristics of a patch antenna integrated with EBG structures in all directions and length direction are similar.

Probability of exceeding the serviceability limit of antenna masts

  • Kammel, Christian
    • Wind and Structures
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    • v.4 no.4
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    • pp.353-366
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    • 2001
  • With respect to serviceability, antenna masts should be designed so that wind-induced motion will not cause unacceptable lack of transmission for broadcasting users and wireless communication. For such antenna masts with directional radio transmission the serviceability limit state is predominantly governed by the tolerable change of the broadcasting angle of the mounted antenna assembly and therefore by the tip distortion of the mast. In this paper it will be shown that refinements of the present state of design of antenna masts are possible by using the statistics of extremes applied to extreme wind situations and by consideration of the statistical and reliability requirements given by the operator such as frequency and return period of passing the serviceability limit.

Sub-Terahertz On-Chip Microstrip Patch Antenna in CMOS with Metal Dummy Structures (메탈 더미 구조를 포함하는 서브 테라헤르츠 CMOS 온칩 마이크로스트립 패치 안테나)

  • Shim, Dongha;Yang, Ji Hoon;Han, Seung Han;Lee, Hyounmin;Kim, Ki Hoon;Kim, Hokyung
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.28 no.6
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    • pp.505-508
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    • 2017
  • This paper analyzes the effect of metal dummy structures in CMOS on antenna performances of a sub-terahertz on-chip microstrip patch antenna. A 400-GHz on-chip antenna is designed in a 45-nm CMOS process, and the resonance frequency and efficiency of the antenna are analyzed depending on the density of metal dummy structures. Antennas integrated with an oscillator are designed and fabricated for verification, and measurements are performed using quasi-optical methods with an FTIR and bolometer. The measurement results shows that the radiated power drops from 420 nW to 90 nW by 6.8 dB due to the dummy structures with the density of 27 %.

Design of Multilayer Composite-Antenna-Structures Considering Adhesive (접착필름의 영향을 고려한 다층 복합재료 안테나 구조 설계)

  • Kim, D.S.;Park, H.C.;Park, W.S.;Hwang, W.
    • Composites Research
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    • v.20 no.2
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    • pp.27-31
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    • 2007
  • "Structural surface becomes an antenna." This term, CAS, indicates antenna embedding in structural surfaces. The CAS is composed of several composite laminates and Nomex honeycombs, and microstrip antenna elements are inserted between layers with designed configurations. Constituent materials are selected considering electrical contributions as well as mechanical performances. Antenna design with adhesive films are impossible because of their thin and rough distributions between honeycomb and substrate. Therefore, adhesive effects on antenna performances in CAS are experimentally investigated, CAS with targeted impedance and radiation characteristics are designed considering adhesive effects. multilayer