• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1946-1949
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• 2002

본 논문에서는 밀리미터파 대역에서 저손실 특성이 우수한 전송선로인 non-radiative dielectric (NRD) guide와 microstrip의 transition에 관해 연구하였다. 본 연구에서 이용된 transition은 aperture coupling을 이용한 것으로 NRD와 microstrip 사이의 aperture를 통하여 magnetic field가 coupling되는 원리이다. Aperture의 구조를 각각 rectangular와 ridge 형태로 설계하였다. 비교를 위해서 설계된 microstrip to microstrip transition의 경우 aperture의 구조를 ridge 형태로 했을 때 rectangular 일 때 보다 삽입손실 특성이 개선되었고 더 넓은 bandwidth를 가지는 것을 알 수 있었다 NRD to microstrip transition의 경우는 bandwidth 면에서 ridge 구조와 rectangular 구조 모두 비슷한 특성을 보였다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.12
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• pp.1198-1204
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• 2013

As a microwave near field probe for near field scanning optical microscope(NSOM) system, H-shaped(ridge type) small aperture is proposed and its performances from the viewpoints of the transmission efficiency(transmission cross section) and spatial confinement(beam spot size) are compared with those of the previous narrow rectangular aperture type. While the transmission efficiencies are comparable to each other for the two structures, the transmitted beam spot size for the proposed H-shaped aperture is much smaller than that for the previous rectangular aperture. This strong point of the H-shaped aperture is expected to significantly improve near-field optical applications such as optical data storage, nanolithography and nanomicroscopy. It is also observed that the transmission efficiency can be improved if the coupling aperture is implemented in the type of the transmission cavity.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.12
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• pp.1300-1305
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• 2014

Equivalent circuits for the waveguide probe with H-shaped small aperture, as a key ingredient of near field microwave microscope, is described along with a working principle of the probe. Small rectangular or circular aperture in comparison with the wavelength behaves like the inductive element. So adding the ridged structure (corresponding to capacitive component) to the small aperture allows the transmission resonance to occur. For verification, we represents the equivalent circuit descriptions for the two types, ridged aperture and cavity types. The values of obtained by use of the equivalent circuit approaches are compared with those obtained by use of the available numerical software. The results are also experimentally verified.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.12
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• pp.2518-2524
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• 2009

This paper presents the backplane effects due to a rectangular aperture size for two-wire transmission line with equal line length crossing the changeable rectangular aperture in an infinite ground backplane. It is used to determine the characteristics of the backplane insertion loss of the transmission line from the load section in accordance with the backplane aperture size. The results show that the insertion gain and insertion loss are obtained for the specific frequency range when the transmission line is closed to the backplane aperture size. The insertion loss is decreased that the aperture horizontal length and vertical length is more than a=50 mm and b=20 mm. The measurements of insertion loss are performed to verify the theoretical analysis.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.5
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• pp.652-659
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• 2012

Shielding effectiveness(SE) of metallic rectangular enclosure with rectangular slit apertures at horizontal polarization (HP) and vertical polarization(VP) is investigated. The magnetic polarizability of the rectangular slit apertures and the resonance modes of the metallic rectangular enclosure are analyzed theoretically. The simulation results based on these theoretical analyses are compared with the measured ones. The dependence of the shielding effectiveness on the location of the calculation probe inside the enclosure is also investigated.

• Journal of Broadcast Engineering
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• v.19 no.1
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• pp.109-117
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• 2014

This paper presents a superresolution restoration technique that can restore high-resolution images from differently blurred low resolution images rather than using the motion information between low-resolution images. In order to restore the super-resolution image the rotatable aperture mask lens system is proposed. The proposed technique does not need to estimate point spread function at each frame. In addition, it does not require image registration because there is no global translational motion between low resolution images. By using a rotatable rectangular aperture, two consecutive captured images provide sufficiently exclusive information for superresolution. Therefore, the proposed method can reduce the registration error between the low-resolution image as well as the calculation amount for superresolution restoration. The existing lens system of the camera can be extended to obtain a superresolution image by only adding an rotatable rectangular aperture mask. Finally, in order to verify the performance of the proposed system, experimental results are performed. By comparing with the existing superresolution methods, the proposed method showed the significant improvements in the sense of spatial resolution.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.9
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• pp.957-967
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• 2008

In this paper, we propose the prediction algorithm of radiation emission from the PCB in an enclosure with a rectangular aperture. PCB scanner is used to measure the near field, which is substituted with an equivalent electric dipole source. Green function and Fourier transform are utilized to represent the electromagnetic fields within and outside the enclosure, respectively. The radiation emission is estimated by using the mode matching technique and surface equivalent theorem. The theoretical results are compared with the measurement to check the accuracy of our analysis.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.7
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• pp.675-682
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• 2011

This paper presents two ground plane effects due to the size of two rectangular apertures for two-wire transmission line with equal line length crossing the changeable rectangular apertures in infinite ground planes. The CST MWS is used to determine the characteristics of the insertion loss of the transmission line from the load section in accordance with the ground plane aperture size. The results show that the insertion gain and the insertion loss are periodically observed for the multiple frequency of the half wavelength resonance by the wire length when the transmission line is nearby to horizontal side or vertical side of the aperture. The measurements of the insertion loss are performed to verify the theoretical analysis.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.1
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• pp.60-66
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• 2009

A new analytical method is presented for the shielding effectiveness(SE) of an enclosure with a dielectric-backed aperture. The previously proposed methods cannot consider the effect of the dielectric on the aperture. The comparisons among our method, previous method, and commercial programs give good correspondence. The method is used to calculate SE with varying permittivity and thickness of dielectric sheet, probe position, width and height of aperture.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.10
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• pp.1034-1039
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• 2002

In this paper, the design of a dual-polarization rectangular microstrip patch antenna with high isolation between two feeding ports excited by using both an aperture-coupled feed (port 1) and a 3-dimensional microstrip feed (port 2) is presented. From the simulation using the commercial program IE3D, the optimum values of the antenna parameters are investigated at both two feed structures and the optimum antenna is designed and fabricated. Experimental results confirmed that an bandwidth of the antenna is about 17 % and the isolation of two ports is great than 30 dB over all frequency bands.