• Current Optics and Photonics
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• v.1 no.6
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• pp.631-636
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• 2017

We firstly develop a straightforward method to generate full $Poincar{\acute{e}}$ beams with any polarization geometry over an arbitrary order $Poincar{\acute{e}}$ sphere. We implement this by coaxial superposition of two orthogonal circular polarized beams with alternative topological charges with the help of a Mach-Zehnder interferometer. Secondly we find the existence of singularity points. And the inner relationship between their characteristics and the order of $Poincar{\acute{e}}$ spheres is also studied. In summary, this work provides a convenient and effective way to generate vector beams and to control their polarization states.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2456-2458
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• 1999

The polarization mode dispersion (PMD) that restricts the transmission bandwidth was investigated in standard long single mode fiber which optimized at 1.3${\mu}m$. Although fiber has perfect circular symmetry, each optical fiber has different refractive index profiles. The investigation of PMD with random mode couplings were conducted in three kinds of fiber by the time-domain interferometric method. By using two manufacturing methods, MCVD(Modified Chemical Vapor Deposition) method and VAD(Vapor Phase Axial Deposition) method, the property of mechanical asymmetric lateral pressure, bending and twisting induced polarization mode dispersion were measured. The concatenated optical fibers were compared with other types.

• ETRI Journal
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• v.41 no.2
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• pp.160-166
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• 2019

A novel analytical method based on the cavity mode theory to design a metasurface (MS) is proposed in this study. We carefully analyzed the phase and amplitude characteristics of the incident wave and transmitted wave, and successfully designed a circular polarization conversion MS by introducing a cutting structure with wider operation bandwidth and higher radiation direction gain compared with that of the original MS. For the measurements, a microstrip antenna operating at 2.4 GHz was used as the source antenna to verify the designed MS. The simulation and measurement results agree well with each other.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.2
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• pp.28.3-29
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• 2015

$Ly{\alpha}$ nebulae, or "$Ly{\alpha}$ blobs", are extended (~100 kpc), bright (L[$Ly{\alpha}$] ~ 1044 erg/s) clouds of $Ly{\alpha}$-emitting gas. The origin of the $Ly{\alpha}$ emission remains unknown, but recent theoretical work suggests that measuring the polarization could discriminate among powering mechanisms. we will discuss current status of $Ly{\alpha}$ polarization observations at high-redshift and our on-going survey program. We will present the first narrow-band, imaging polarimetry of a $Ly{\alpha}$ blob, B3 J2330+3927 at z=3.09, with an embedded, radio-loud AGN (C. You et al. in prep.). The AGN lies near the blob's $Ly{\alpha}$ emission peak and its radio lobes align roughly with the blob's semi-major axis. With the SPOL polarimeter on the MMT telescope, we map the polarization in a grid of circular apertures of radius 0.6" (4.4 kpc), detecting a significant (>$2{\sigma}$) polarization fraction P% in 10 apertures and achieving strong upper-limits (as low as 2%) elsewhere. The degree of the polarization map increases from P% ~ 5% at ~5 kpc from the blob center to ~20% at the outer part (~30 kpc). The detections are distributed asymmetrically, roughly along the blob's major axis. The polarization angles (${\Theta}$) are mostly perpendicular to this axis. These results are consistent with the picture that $Ly{\alpha}$ photons produced at the AGN (or the host galaxy) are resonantly scattered away from the center. Higher polarization fraction on the radio jet suggests that the gas is more optically thin along the jet than the off-axis region.

• Journal of electromagnetic engineering and science
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• v.5 no.3
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• pp.132-139
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• 2005

Wireless bio-signal sensing system, which is based on the principle of Doppler radar, can measure a respiration and heart rates with a periodic movement of skin and muscle near the heart. Though the sensing monostatic system using a circulator has been studied, this bistatic system can be improved by using a circular polarized antenna which has a high isolation between transmitter and receiver. In this paper, we measured the bio-signal without the direct contact with the person. The design of each system and experimental results are discussed.

• Korean Journal of Optics and Photonics
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• v.4 no.2
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• pp.168-172
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• 1993

We measured the spectral transmittance of the cholesteric mixtures of ZLI-1167 and CB15 for various weight fractions of CB15 in the mixture to find out the relationship between the center wavelength of the selective reflection band and the weight fraction of CB15 in the mixture. Left handed circular polarizer for 632.8 nm was designed and fabricated with this mixture whose weight fraction of CB15 was 33.19%. The ellipticity of the elliptical polarization of the transmitted light was measured to be 0.98 showing excellent property of the CLC circular polarizer.

• Journal of Astronomy and Space Sciences
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• v.26 no.3
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• pp.345-354
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• 2009

A stepped septum polarizer has been designed and fabricated for the 43 GHz band KVN receiver system. The dual-circular polarizer converts left and right hand circularly polarized signals into linear polarizations in two separated rectangular waveguides. Measurements show that the performance of the designed septum polarizer covering 42-48 GHz frequency band is adequate to meet the requirement of KVN receivers. Especially, a polarizer for the KVN receiver of 85-95 GHz frequency band can be fabricated by scaling the dimensions of the septum polarizer developed in this paper.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.6 no.3
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• pp.101-110
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• 2007

This study has designed a circular polarization antenna for UHF bandwidth RFID reader. As a result of performance test of the antenna designed it is found that return loss (S11) is about -45.529dB at 914MHz, which is relatively small, and antenna gain is about 6.09dBi. It has also been confirmed that $50{\Omega}$ impedance matching is about $50.48{$\Omega}$ and it can be applied to every RFID reader. Therefore, the antenna is designed to have higher gain of circular polarization by improving reception, which is one of the most important parameters of RFID reader and is expected to be extensively used to recognize multi-tag in the distance.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.8
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• pp.119-124
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• 2004

In this paper, we are designed and fabricated circular polarization microstrip patch antenna of 5［GH］z bandwidth for the wireless LAN and the ISM. We are proposed new structure that removed the section which intersected at a right angle and were composed to four separated slots. The antenna of proposed structure could solve parasitic elements from intersected in a right angle and weak coupling efficiency from asymmetry between feed line and a slot. The proposed cross slots antenna is easily impedance matching and increased impedance bandwidth. Also this is increased efficiency and a bandwidth of antenna and reduce back lobe of radiation pattern. We designed 2${\times}$2 array antenna of 5［GHz］ band. It took impedance bandwidth 280［MHz］(VSWR < 1.5) and gam 12.5［dBi］

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.4
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• pp.343-350
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• 2003

Circularly polarized-dual band antenna for GPS(Global Positioning System) and satellite radio system is developed and measured. Both circular polarization and overall antenna dimension reduction are achieved by placing a partially filled high-permittivity substrate under radiating edges. The bandwidth is also improved by choosing an optimal geometric configuration with a partially filled high permittivity substrate. The proposed antenna can be installed on moving vehicles or ships.