• Title, Summary, Keyword: 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.

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.

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.

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 Scattering Property of Cascaded Polarization Controllers

  • Muga, Nelson J.;Ferreira, Mario F.;Pinto, Armando Nolasco
    • ETRI Journal
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    • v.29 no.6
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    • pp.838-840
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    • 2007
  • The relation between the allowed range of variation of polarization controller wave-plates angles and the respective polarization scattering properties is investigated. It is demonstrated that a nearly uniform polarization scattering over the Poincare sphere is obtained using a concatenation of three polarization controllers with angles randomly changed between $-{\pi}$/4 and ${\pi}$/4. It is also shown that an improvement of the scattering properties is obtained if the configuration angles are allowed to change between $-{\pi}$/2 and ${\pi}$/2.

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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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Suppression of polarization effects in Er-doped fiber source for gyroscope by polarization scrambling (자이로용 Er-첨가 광섬유 광원에서 편광 스크램블링을 이용한 편광효과의 억제)

  • 김택중;진영준;박희갑
    • Korean Journal of Optics and Photonics
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    • v.14 no.4
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    • pp.449-453
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    • 2003
  • In a broadband erbium-doped fiber source for fiber optic gyroscope, a pump-polarization scrambling scheme is used to suppress the polarization dependence of the source mean wavelength. The degree of polarization of the pump is reduced to 1.4% by applying proper modulation depth to the polarization modulator where 10 m-long single-mode fiber is wound on a cylindrical PZT. In the case of using the pump-polarization scrambler as well as the output depolarizer, the mean-wavelength variations due to the random change of polarization are measured to be less than our measurement limit of 5 ppm.

Integrated-Optic Polarization Controlling Devices Using Electro-Optic Polymers

  • Oh, Min-Cheol;Hwang, Wol-Yon;Kim, Jang-Joo
    • ETRI Journal
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    • v.18 no.4
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    • pp.287-299
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    • 1997
  • Integrated-optic polarization controlling devices such as polarizers, polarization splitters, and polarization converters, are proposed and demonstrated in nonlinear optic polymers. Poling-induced birefringence in electro-optic polymers is exploited to fabricate the devices. The polymeric waveguide polarizers show low excess losses, and extinction ratios of 20.7 dB and 17.1 dB for TM-pass and TE-pass polarizers, respectively. The polymeric waveguide polarization splitters exhibit TE-TM mode splittings with crosstalk of 14.2 dB and 10.1 dB for TM and TE mode splittings, respectively. The polymeric waveguide polarization converters show successful TE/TM polarization mode conversion with conversion efficiencies of higher than 30 dB. The device employs poling-induced waveguides which have slowly rotating azimuth angle of optic axis along the light propagation direction. The novel polarization converter is insensitive to wavelength and easier to fabricate than the other polarization converters containing periodic structures.

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Polarization Splitter Made of the Side-Polished Fiber Coupler Including a thin Metal Intermediate Layer (얇은 중간 금속층을 포함한 측면 연마 광섬유 결합기를 이용한 편광 분리기)

  • 김광택;이준옥
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.40 no.9
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    • pp.651-657
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    • 2003
  • We have demonstrated an in-line polarization splitter based on a side-polished fiber coupler including a thin metal intermediate layer. The experimental results revealed that the metal layer with proper thickness prevents TE polarization component from optical coupling between two contacted side-polished fibers, whereas it allows TM polarization component to the coupling. The design and fabrication techniques about the polarization splitter exploiting the side-polished fibers have been presented. The fabricated polarization splitter exhibited 18dB and 23dB of isolation ratio for TE polarization and TM polarization, respectively. The measured insertion loss for TE and TM polarization was 0.7dB and 1.3dB, respectively.

Effect of Chirp on Polarization Mode Dispersion and Polarization-Dependent Loss (PMD와 PDL에 미치는 chirp의 영향)

  • Yoon, Il-Yong;Lee, Yong-Wook;Lee, Byoung-Ho
    • Proceedings of the KIEE Conference
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    • pp.1939-1940
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    • 2002
  • Numerical simulation for effect of chirp on PMD and PDL was accomplished. we assumed two uniform fiber concatenation with both polarization mode dispersion and polarization-dependent loss. We showed that polarization mode dispersion is increased with chirp parameter and polarization-dependent loss is decreased with chirp. And we accomplished mathematical analysis.

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