• Title/Summary/Keyword: circularly polarized

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Design and Fabrication of Circularly Polarized Antenna for 2.45GHz RFID Application (2.45GHz RFID용 원형편파안테나의 설계 및 제작)

  • Park, Jeong-Heum
    • Journal of the Institute of Electronics Engineers of Korea TE
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    • v.42 no.4
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    • pp.63-68
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    • 2005
  • In this paper, the single coaxial fed and circularly polarized patch antenna for the RFID system in 2.45GHz ISM band has been fabricated. The simulation by HFSS, electro-magnetic field simulator was executed in order to decide the location of feed which is difficult to be analysed. The simulated result has the same tendency as the measured one in the view of input impedance with the variation of feed location. VSWR of fabricated antenna is low($\leq$1.2) even in comparatively high dielectric loss epoxy substrate(FR4), and this value is enough for the application of RFID reader antenna.

Improvements of the OFDM System Performance By Using the Characteristic of Circularly Polarized Waves and Carrier Interferometry Signals (원형편파특성과 반송파 간섭신호특성을 적용한 OFDM 시스템 성능 개선)

  • Ahn, Je-Sung;Ha, Deock-Ho
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.8A
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    • pp.794-801
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    • 2007
  • In this paper, in order to enhance the performance improvements of both BER and PAPR characteristic for the conventional OFDM system, both circularly polarized waves and carrier interferometry signals which shows the robustic fading reduction effect are applied to the system, and then the performance of the proposed system has been evaluated by computer simulation. From the analysis, it can be seen that the system BER performance can be improved by 2 or 3 dB. Furthermore, it can be also seen that the PAPR characteristic can be markedly reduced.

Design for the Circularly Polarized Microstrip Cross Dipole Array Antenna by Electromagnetic Coupled Technique (전자기 결합기법을 이용한 원편파 마이크로스트립 크로스 다이폴 어레이 안테나의 설계)

  • 민경식;임정남
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.12 no.1
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    • pp.50-57
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    • 2001
  • This paper describes a design for the circularly polarized microstrip EMC cross dipole array antenna with the wide bandwidth. To realize the characteristics of wide bandwidth and circular polarization, the electromagnetic-coupled cross dipole element is proposed. The optimum design parameters of a circularly polarized EMC cross dipole element are calculated by the FDTD and the Ensemble. To obtain the uniform aperture illumination of electric field in an array, offset technique that the cross dipole elements are alternatively arranged on center of the microstrip feed line is adopted. In 20-element array design, the calculated axial ratio and gain are about 0.1dB and 9.9 dBi at 12 GHz, respectively, The frequency characteristics of a fabricated 20-element array antenna are measured. The calculated results agree well with the measured ones.

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A Two-Element Circularly-Polarized Antenna Array for UHF-Band RFID Reader Applications

  • Park Joung-Min;Kim Yun-Mi;Ahn Bierng-Chearl;Park Chan-Sik;Cha Eun-Jong
    • Journal of electromagnetic engineering and science
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    • v.6 no.1
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    • pp.36-46
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    • 2006
  • In this paper, we present a two-element circularly-polarized antenna array for UHF-band RFID reader applications. The antenna element in the array is a comer-truncated rectangular patch placed on a thick plastic-foam dielectric. The patch is fed on one of its edges by a microstrip line printed on a separate thin substrate. The array antenna is fed by a microstrip power divider. Parametric studies on the patch are carried out, from which an optimum design of a single antenna element is derived. The element spacing and the feed network of the array are investigated. A commercial electromagnetic software is employed in the analysis and design of the antenna. The designed array is fabricated and tested. Measurements show good performance characteristics of the fabricated antenna: a 11.2-dBi gain, a reflection coefficient of - 14 dB, an axial ratio less than 3 dB over 3-dB beamwidths of 40 and 60 degrees on two principal planes.

Design of Circularly Polarized Array Antenna for 5.8GHz Microwave Wireless Power Transmission (5.8GHz 마이크로파 무선전력전송을 위한 원형 편파 배열 안테나 설계)

  • Lee, Seong Hun;Son, Myung Sik
    • Journal of the Semiconductor & Display Technology
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    • v.17 no.2
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    • pp.20-25
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    • 2018
  • In this paper, we have designed circularly polarized array antenna for 5.8GHz microwave wireless power transmission. To obtain high antenna gain, we studied a single patch antenna, a $2{\times}1$ array antenna, a $2{\times}2$ array antenna, a $2{\times}4$ array antenna, and a $4{\times}4$ array antenna. Commonly, characteristics of each antenna have a frequency of 5.8 GHz and Right Hand Circular Polarization(RHCP) of circular polarization. Also, the results were obtained with the design to each antenna that the return loss was less than -10dB and the axial ratio was less than 3dB. The gain of the antennas was 6.08dBi for a single patch antenna, 9.69dBi for a $2{\times}1$ array antenna, 12.99dBi for a $2{\times}2$ array antenna, 15.72dBi for a $2{\times}4$ array antenna and 18.39dBi for a $4{\times}4$ array antenna. When the elements of the array antenna were increased, it was confirmed that it increased by about 3dBi.

Characteristics of Circularly Polarized Antenna (원형편파 안테나 특성 연구)

  • Park, Yong-Wook
    • The Journal of the Korea institute of electronic communication sciences
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    • v.5 no.6
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    • pp.563-567
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    • 2010
  • In this paper, circularly polarized micro-strip GPS of 1.57 GHz and DMB of 2.63~2.65GHz antenna have been studied. In order to improve of frequency properties, parameters such as patch size, corner truncated type, and feed positions were simulated using HFSS program. GPS and DMB antenna were fabricated and characteristics were measured using network analyzer.

Production of Hyperpolarized 129Xe Using Spin Exchange Optical Pumping

  • Kavtanyuk, Vladimir Vladimirovich;Kim, Wooyoung;Ando, Yu;Chebotaryov, Sergey;Seon, Yonggeun;Tan, Joshua Artem
    • Journal of the Korean Physical Society
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    • v.73 no.10
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    • pp.1458-1465
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    • 2018
  • We present a constructed setup for polarizing $^{129}Xe$ noble gas. Hyperpolarized $^{129}Xe$ has been obtained via spin exchange with an optically pumped rubidium vapor. Optical pumping is based on polarizing the valence electron of rubidium by the resonant absorption of a circularly polarized laser light. The magnetic field of 30 G was used for obtaining $^{129}Xe$ polarization. The apparatus for detecting polarization is a nuclear magnetic resonance spectrometer. The highest $^{129}Xe$ polarization of 54% has been obtained using 60 W circularly polarized laser light with wavelength of 794.7 nm. The measured longitudinal relaxation time of the hyperpolarized $^{129}Xe$ was 72.3 minutes.

On the Utilization of Polarization Dependency Acquired by an Intentionally Misaligned Antenna Array for Mitigation of GPS Jammers

  • Park, Kwansik;Seo, Jiwon
    • Journal of Positioning, Navigation, and Timing
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    • v.10 no.4
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    • pp.291-296
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    • 2021
  • Recently, the dual-polarized antenna array has drawn attention due to the dependency of its signal processing gain on the signal polarization. Even though this polarization dependency makes it possible to mitigate a non-right-hand circularly polarized (non-RHCP) jamming signal from the same direction as a GPS signal, the dual-polarized antennas are not yet widely used for various applications. This study suggests a method that can acquire the polarization dependency of the signal-processing gain by intentionally misaligning antenna elements in a single-polarized antenna array. The simulation results show that the proposed method can successfully mitigate a non-RHCP jammer from the same direction as a GPS signal as if a dual-polarized antenna array does and provide comparable signal-to-jammer-plus-noise ratio (SJNR) performance with a completely aligned single-polarized antenna array and a dual-polarized antenna array.

Study on Circularly Polarized Micro-strip GPS Antenna (원형편파 마이크로 스트립 GPS 안테나의 연구)

  • Park, Yong-Wook
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.10
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    • pp.3880-3884
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    • 2010
  • In this paper, circularly polarized micro-strip GPS antenna has been designed and fabricated. In order to improve of frequency properties, patch size, corner truncated size and feed positions were simulated using HFSS simulation program. Micro-strip GPS antenna was fabricated on the FR4 substrate of dielectric constant 4.4. The fabricated GPS antenna has that center frequency is 1.575GHz and insertion loss is -34.50dB.

Heavy ion effects on mode conversion between electron and proton whistlers : A simulation study

  • 김은화;이동훈
    • Bulletin of the Korean Space Science Society
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    • 2003.10a
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    • pp.37-37
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    • 2003
  • Electron whistlers frequently excite proton whistlers. The proton whistlers appear on the dynamic spectrum as rising tones, which start after the reception of a short electron whistler, asymptotically approaching the local proton gyro-frequency. The proton whistlers are dispersed forms of lightning impulses and their dispersion can be explained by the effects of heavy ions such as H+ and He+ on the propagation of an electromagnetic wave in the ionosphere. In the ionosphere, a right-handed circularly-polarized electron whistler becomes coupled to a left-handed circularly-polarized proton whistler when the frequency becomes close to a cross-over frequency. By adopting the multi-fluid numerical wave model, we examine how the mode coupling varies as the ion composition changes along altitude in the mid-latitude ionosphere. The time histories and dynamic spectra of electric fields are presented. In addition, we compare our results with the previous theoretical and observational studies.

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