• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1394-1397
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• 2005

Hyundai LCD Inc. and LUXELL Technologies Inc. have jointly developed a 1.5" passive matrix full color OLED display ($132{\times}RGB{\times}96$, 111ppi) with characteristics of enhanced contrast ratio using black layer technology. This prototype ECR OLED was fabricated with the structure of ITO/HIL/HTL/RGB EML/HBL/ETL/LiF/Black Layer/Cathode and showed significant improvement of contrast ratio comparing with that of non-filtered OLED as well as compatible with circular polarizer OLED

• Journal of Electrical Engineering and Technology
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• v.12 no.3
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• pp.1250-1256
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• 2017

This paper proposes the design of microstrip patch antennas for dual-band polarization adjustment. The antenna has a multi-layer structure for dual-band operation, and each layer contains a resonating patch with surrounding strips separated into two parts. The antenna polarization is adjusted by varying the separated positions of the strips, while fixing other design parameters. To demonstrate the feasibility, an antenna sample with right-hand circular polarization is fabricated, and its antenna characteristics are measured in a full anechoic chamber. The operating principle of polarization adjustment in the dual frequency bands is also verified by observing near electromagnetic fields and the magnetic surface current density around the antenna.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.12
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• pp.1215-1218
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• 2013

A 90-deg phase shifter using corrugated square waveguide structure for 86 GHz band VLBI(Very Long Baseline Interferometry) dual-circular polarization observation has been developed. The 90-deg phase shifter was designed to have two corrugated walls inside the square waveguide so that the vertically and horizontally polarized waves at the output port have phase differences of $90{\pm}3.3$ deg across 85~115 GHz. Measurements show that the return and insertion losses for the both polarizations are better than 17 dB and 0.25 dB, respectively. The axial ratio is estimated to be less than 0.6 dB within the required frequency band.

• Journal of IKEEE
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• v.26 no.3
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• pp.416-421
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• 2022

In this study, we present a fully automated system that combines camera technology with liquid crystal technology to create a polarization camera capable of detecting the partial linear polarization of light reflected from an object. The use of twisted nematic (TN) liquid crystals that electro-optically modulate the polarization plane of light eliminates the need to mechanically rotate the polarizing filter in front of the camera lens. Images obtained using these techniques are imaged by computer software. In addition, liquid crystal panels have been produced in a square shape, but many camera lenses are usually round, and lighting or other driving units are installed around the lens, so space is optimized through the application of a circular liquid crystal display. Through the development of this technology, an electrically switchable and space-optimized liquid crystal polarizer is developed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.5 s.108
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• pp.461-475
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• 2006

In this paper, it is described about the tri-band mobile antenna system design to provide broadband multimedia and direct broadcasting services using goo-stationary Koreasat 3, simultaneously operated in Ka/K/Ku band. The radiating part of the antenna system with a fan beam characteristic in the elevation plane is composed of the quasi-offset dual shaped reflector and the tri-band feeder. The tri-band feeder is also composed of the Ka/K dual band feeder with the protruding dielectric rod, the circular polarizer, the ortho-mode transducer and the circular-polarized Ku band feed array. Especially, the Ka/K dual band circular polarizer was realized firstly using the comb-type structure. For fast satellite-tracking on the movement, the Ku band feed array has the structure of the $2{\times}2$ active phased array which can make electrical beams. And, the circular-polarized characteristic in the feed array was improved by $90^{\circ}$ rotating arrangement of four radiating elements polarized circularly by a $90^{\circ}$ hybrid coupler, respectively. Four beam forming channels to make electrical beams at Ku band are divided into the main beam channel and the tracking beam channel in the output, and noise temperature characteristics of each channel were analyzed on the basis of the contributions of internal sub_units. From the fabricated antenna system, the output power at $P_{1dBc}$ of Ka_Tx channel was measured more than 34.1 dBm and the measured noise figures of K/Ku_Rx channels were less than 2.4 dB and 1.5 dB, respectively, over the operating band. The radiation patterns with co- and cross-polarization in the tri-band were measured using a near-field measurement in the anechoic chamber. Especially, Ku radiation patterns were measured after correcting each initial phase of active channels with partial radiation patterns obtained from the independent excitation of each channel. The antenna gains measured in Ka/K/Ku band of the antenna system were more than 39.6 dBi, 37.5 dBi, 29.6 dBi, respectively. And, the antenna system showed good system performances such as Ka_Tx EIRP more than 43.7 dBW and K/Ku_Rx G/T more than 13.2 dB/K and 7.12 dB/K, respectively.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.11
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• pp.1471-1476
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• 2018

In this paper, a high-gain antenna for satellite communication is proposed. The proposed antenna consists of septum polarizer, circular waveguide, Hat-feed structure that has a high-gain and efficiency. Especially, it is smaller and lighter than the conventional satellite communication antennas by applying a hat-feed structure. The measured results show that received gain of proposed antenna is better than 29.9 dBi and transmitted gain of proposed antenna is better than 30.5 dBi. The co-polarized and cross-polarized radiation patterns comply with ITU-RR Ap.8 and ITU-R S.731-1 that are recommended by International Telecommunication Union. The designed high-gain antenna for satellite communication is expected to be used for OTM and airborne satellite systems.

• Journal of Korean Ophthalmic Optics Society
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• v.6 no.2
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• pp.11-16
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• 2001

The polariscope to measure :he stress in lens was made up quarter-wave plate polarizer and we analyzed two components of light's wave $E_1$ and $E_2$ following the steps. It is clear that the principal-stress difference ${\sigma}_1-{\sigma}_2$ can be determined in 2-D model if fringe order N is measured each point in sample moreover. the optical axes of sample coincide with the principal-stress directions. The birefringence acted to a light wave and a phase retardation were in proportioned to the principal-stressed difference (${\sigma}_1-{\sigma}_2$) and the intensity of final light wave was proportioned to $sin^2({\Delta}/2)$, when ${\Delta}/2=n^{\pi}$ (n=0, 1, 2, ...) and the extinction occurs. As a experimental result, the extinction band shifted owing to a magnitude of lens' external stress.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.1
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• pp.90-97
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• 2014

In this paper, we have designed the antenna for Korea SAT-5 Satellite Communication which can use Ka band in the earth station. The antenna structure consist of the the dual-offset gregorian reflector that has high gain and efficiency, the corrugated horn that has symmetric radiation patterns and low side lobe levels, the iris polarizer that make circular polarization and the OrthoMode Transducer that separate transmitting and receiving signals. The designed antenna gain is more than 45.7dBi in Tx-band which use LHCP and 42.0dBi in Rx-band which use RHCP. The co-polarized and cross-polarized radiation pattern comply with ITU-R S.580-6 and S.731-1 that are recommended by International Telecommunication Union in the geostationary satellite. The Axial ratio is less than 1.0dB in Tx-band and 1.5dB in Rx-band that meet MIL-STD-188-164A.

• Journal of the Korean Society for Nondestructive Testing
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• v.21 no.2
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• pp.189-196
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• 2001

Photoelasticity is one of the most widely used methods for whole field stress analysis. In photoelasticity, the difference and the directions of the principal stresses we given isochromatic and isoclinic fringe patterns. Conventionally, principal stress directions are measured manually by relating the polarizer and analyzer of a plane polariscope at the same time. This is known to be the Tardy compensation method. This measurement can be very tedious and time consuming in whole field analysis. It is not possible to separate isoclincs from photoelastic fringes by conventional photoelastic technique. In this study, photoelastic theory is represented by Jones matrices and 4-steps and 8-steps phase shifting methods are described A feasibility study using computer simulation is done to separate isoclincs and isochomatics from photoelastic fringes of a circular disk under diametrical compression. Fringe patterns of the disk are generated using stress optic law. The magnitudes of isoclincs and isochromatics obtained from 8-step phase shifting method are compared with those of theories. From computer simulation, it is verified to separate isoclincs and isochomatics from photoelastic fringes.