• Title, Summary, Keyword: circular polarization

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Circular Polarization Diversity in Indoor Wireless Mobile Environments

  • Ha, Deock-Ho;Ko, Yeon-Hwa;An, Jae-Sung;Kim, Tai-Hong
    • Journal of electromagnetic engineering and science
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    • v.4 no.3
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    • pp.128-136
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    • 2004
  • In this paper,. with the aim of achieving the expected performance improvement for a polarization diversity system, we analyzed two-branch polarization diversity at the receiving end of a mobile link which a transmitter emits circularly polarized wave. In this analysis, to calculate the correlation coefficient considered by XPD(cross polarization discrimination) between the two received signals, a simple theoretical model of circular polarization diversity is adopted. From the analysis results, it is clearly seen that the correlation coefficient of circular polarization diversity evaluated by the XPD is less than that of conventional linear polarization diversity. And also, we designed and implemented a circular polarization diversity system with micro-strip antenna. By using the circular polarization diversity system, we analyzed the measured data in indoor NLOS(Non-Line-Of-Sight) environments. From this analysis results, it is also clearly seen that the diversity effect of circular polarization diversity system shows better performance compared to the conventional linear diversity system by about 3 dB high.

The Circular Polarization Diversity Effect Considering XPD Factor in an Indoor Radio Propagation Environment

  • Ahn Je-Sung;Ha Deock-Ho;Cho Pyung-Dong
    • Journal of electromagnetic engineering and science
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    • v.6 no.1
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    • pp.24-29
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    • 2006
  • In this paper, we analyzed new two-branch polarization diversity at the receiving end of a mobile link which a transmitter emits circularly polarized wave. To analyze the correlation coefficient considered by XPD(Cross Polarization Discrimination) between the two received signals, a simple theoretical model of circular polarization diversity is adopted and experimental measurements are also conducted. From both theoretical and measurement results, it can be seen that the proposed circular polarization diversity scheme is more effective than that of the conventional linear polarization diversity.

Polarization-Diversity Cross-Shaped Patch Antenna for Satellite-DMB Systems

  • Lim, Jong-Hyuk;Back, Gyu-Tae;Yun, Tae-Yeoul
    • ETRI Journal
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    • v.32 no.2
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    • pp.312-318
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    • 2010
  • A small reconfigurable patch antenna is proposed to achieve polarization diversity for digital multimedia broadcasting systems at 2.6 GHz. To obtain polarization diversity, a pair of on-slit PIN diodes is inserted in each diagonal of a cross-shaped patch. Thus, four PIN-diodes on these slits are utilized to change the connection of the slits and thus achieve polarization. Bias circuits for the diodes are allocated in the cutting corner of the cross-shaped patch to minimize the antenna size. The antenna produces left-hand circular polarization, right-hand circular polarization, or linear polarization, depending on the PIN-diode status. Analysis of circular polarization operation is explicated. Measurements show a gain of about 1.5 dB, a cross polarization of about -20 dB, and an axial ratio of about 2.5 dB.

A Corner-Fed Microstrip Circular Antenna with Switchable Polarization

  • Sung, Young-Je
    • ETRI Journal
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    • v.30 no.5
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    • pp.718-722
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    • 2008
  • In this paper, a design for a novel microstrip antenna with circular polarization diversity is proposed and experimentally investigated. This antenna is excited by a microstrip line, which is located at the corner of a circular patch. The polarization state can be switched electrically by setting a diode to on or off. The novel structure we describe here enables the optimization of the input match for both polarizations. From the measured result, good axial ratios are observed at the operating frequencies.

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The Fabrication and Performance Estimation of Circularly Polarization Diversity System for Multipath Fading Reduction (다중경로페이딩 경감을 위한 원편파 다이버시티 시스템 제작 및 성능 평가)

  • 이주현;김판신;안재성;김태홍;고연화;김흥진;하덕호
    • Proceedings of the IEEK Conference
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    • pp.609-612
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    • 2003
  • For combating multipath fading in wireless radio environment, diversity schemes is useful. In this paper, for performance improvement of polarization diversity system, we analyzed a two-branch polarization diversity at the receiving end of a mobile link when the transmitter emits a circularly polarized wave. And In order to calculate the correlation coefficient considering the XPD(cross polarization discrimination) between the received signals for the two diversity branches, a simple theoretical model of circular polarization diversity is adopted and calculate correlation coefficient. From the analysis results, it is seen that the correlation coefficient of circular polarization diversity evaluated by the XPD is less than that of vertical polarization diversity. And also, we designed and fabricated circular polarization diversity system with microstrip antenna. we analyzed data measured in indoor NLOS environment using fabricated circular polarization diversity system. From the measurement results, it is clearly seen that the diversity effect of circular polarization diversity system is higher 3dB than vertical polarization diversity system.

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Circularly polarized soft X-ray generation by Co/Pt thin film polarizer with perpendicular magnetic anisotropy

  • Lee, Sang-Hyuk;Huang, Lin;Lee, Jae-Woong;Kim, Namdong;Shin, Hyun-Joon;Jeong, Jong-Ryul;Hwang, Chanyong;Kim, Dong-Hyun
    • Current Applied Physics
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    • v.18 no.11
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    • pp.1196-1200
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    • 2018
  • We have experimentally demonstrated circular polarization generation from linear polarized soft X-ray at synchrotron by adopting a thin magnetic film polarizer. Polarizer is composed of Co/Pt multilayer with a perpendicular magnetic anisotropy, which allows us to easily accommodate without needing any tilting angle into the measurement setup since the circular polarization is generated for the X-ray with normal incidence and transmission. Generated circular polarization is examined by observing magnetic domain features based on the X-ray magnetic circular dichroism, where~11% of circular component is estimated compared to the case of full circular polarization.

CP-OFDM System using Circular Polarization (원편파를 이용한 CP-OFDM 시스템)

  • 김병옥;하덕호
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
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    • pp.34-38
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    • 2001
  • This paper proposes a CP-OFDM(Orthogonal Frequency Division Multiplexing using Circular Polarization) system for improving the system performance. The circular polarization has a characteristic that it cannot receive the reflected waves which are reflected by odd times. By reducing the influences of the reflected waves, the circular polarization can reduce the time delay spread and the inter-channel interference. The guard interval needed for the OFDM frame can be minimized and the orthogonality between subchannels can be improved by using circular polarization. Therefore the proposed CP-OFDM system can improve the system performance as well as the spectrum efficiency. Both theoretical analysis and system simulation results are described.

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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.

Investigating Electromagnetic Power Transfer Ratio of Circular Polarizing Planar Metasurface Lens

  • Lee, ChangHyeong;Han, DaJung;Khattak, Muhamad Kamran;Kahng, Sungtek
    • Journal of Satellite, Information and Communications
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    • v.11 no.1
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    • pp.37-40
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    • 2016
  • We designed an antenna structure with the circular polarization metamaterial superstrate which increases the directivity of the primary antenna as a lens. The metamaterial superstrate removes the necessity of the array antenna and complicated feed. Plus, it provides the Fabry-perot cavity with the circular polarization. With regard to the primary antenna, a CRLH antenna is adopted to have the size-reduction from the conventional half-wavelength patch antenna.

A Study on the Design of Polarization Selective Antenna for UHF RFID System (UHF RFID 시스템을 위한 Polarization Selective 안테나 설계 연구)

  • Lee, Sa-Won;Song, Woo-Yong
    • The Journal of Advanced Navigation Technology
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    • v.14 no.2
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    • pp.170-175
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    • 2010
  • This article proposed polarization selective antenna for UHF RFID system. The proposed antenna is consist of microstrip patch antenna with dual feeding and two SPDT switches and a SP4T switch and 3dB hybrid coupler. Through control of voltage of switches, the proposed reader antenna can select horizontally linear polarization, vertically linear polarization, left-hand circular polarization (LHCP) and right hand circular polarization (RHCP). The proposed reader antenna satisfied 2:1 VSWR at 902MHz ~ 928MHz. and 3dB under AR(axial ratio). And it can select appropriative polarization with user environment and tag polarization. So it minimize PLF and increased reading distance.