• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.1
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• pp.87-94
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• 2008

This paper proposes a high-gain monopulse antenna using the folded reflectarray for a monopulse target-tracking radar systems designed at the center frequency of 94 GHz. In target-tracking radar systems, the angle of arrival of the incoming wave Is determined by comparing the signal received on two or more non-coincident antenna patterns. This is the physical basis of most target-tracking techniques and the comparison is made simultaneously in a monopulse radar systems. In this paper, the antenna consists of polarizing grid, reflectarray, multimode feed horn, and comparator implemented by wavguide. The antenna is able to have three radiation patterns by using the monopulse feed systems assembled by multimode feed horn and comparator. The antenna demonstrates maximum gains 36dB, 33.5dB and 27.2dB at sum mode, azimuth mode, and evevation mode respectively.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.3
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• pp.9-15
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• 2011

The microstrip reflectarray antenna is rapidly becoming an attractive alternative solution to the traditional parabolic reflector antenna. However, the bandwidth of the microstrip reflectarray using the single layer structure is very narrow. To obtain wide bandwidth characteristic, the microstrip reflectarray using the multi-layer structure has been used, but it has some disadvantages such as high cost and complicated design. In this paper, to obtain low cost and wide bandwidth, the microstrip reflectarray antenna composed of square patch with two U-slots using the single-layer structure is proposed. The proposed antenna demonstrate radiation efficiency closed to 55.5 % and 1 dB gain bandwidth over 14 % at 12.5 GHz.

• Journal of IKEEE
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• v.25 no.2
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• pp.408-411
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• 2021

This paper presents a new reflectarray antenna capable with 1-bit switchable capability for W-band beamforming network. The proposed antenna has been optimized using two unit-cells with sizes of 1.0 mm and 1.3 mm to form a total number of 193 radiating elements on a square aperture surface of length 30 mm. These radiating elements are spaced 0.5 wavelengths apart and fed by a 15 dBi pyramidal horn antenna as the feed antenna placed 53 mm away from the aperture center. The proposed reflectarray achieves a realized peak gain of 22.52 dBi, a half-power beamwidth of 5.1° in both E- and H-planes at the test frequency of 80 GHz and operates over a wide bandwidth from 74 GHz to 90 GHz.

• Journal of IKEEE
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• v.26 no.1
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• pp.137-140
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• 2022

In this paper, we proposed a new W-band monopulse tracking system based on reflectarray antenna structure. The proposed reflectarray antenna monopulse tracking system consists of four feed horn antennas and a planar reflector using a microstrip reflectarray. The four feed horn antennas have a gain of 10 dBi and a half-power beam-width of 56 degrees symmetrically in the E/H plane. It was confirmed that the reflectarray antenna using one feed horn antenna has a size of 41.8 × 41.8 mm², a gain of 26.8 dBi, and a half-power beam-width of about 5.6 degrees. The reflectarray monopulse tracking system using 4 feeding horn antennas is well matched from 75 GHz to 90 GHz, and the isolation is secured by more than 10 dB. Finally, the proposed system shows the tracking range of 5.98 degrees and the tracking error range was 0.02 degrees.

• International Journal of Contents
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• v.7 no.4
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• pp.44-49
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• 2011

The scattering solutions for multiple rectangular metallic gratings in a perfectly conducting plane excited by the TE and TM delta sources are presented using an overlapping T-block method. A reflectarray composed of rectangular metallic gratings shows fanbeam radiation patterns that are useful for an electromagnetic fence. The scattering characteristics of multiple rectangular gratings were computed in terms of total radiated power and antenna directivity. The design method of a fan-beam reflectarray to obtain high directivity was also compared with superdirective radiation and parabolic reflector phase.

• Aerospace Engineering and Technology
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• v.12 no.2
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• pp.140-146
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• 2013

In this study, we discuss about the printed reflectarray antenna design for parabolic reflector volume reduction. For this, we simulated and measured the phase characteristics of the unit array element of reflectarray antenna using waveguide simulator. As a results, the maximum phase variation is $298^{\circ}$ by simulation, the average phase variation is $309^{\circ}$ by measurement in 10GHz. And the printed Reflectarray antenna gain is 28.3dBi, 3dB beamwidth is E-plane $5.1^{\circ}$, H-plane $5.2^{\circ}$, sidelobe level is E-plane -11.4dB, H-plane -17.6dB.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.11
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• pp.937-950
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• 2015

Microstrip reflectarray is an antenna which controls its radiation pattern with a number of reflective elements. Conventionally, the reflectarray has been researched to replace curved reflector antennas. In this paper, design theories of reflectarray is briefly introduced, and research trends of high gain and broadband reflectarrays are reviewed. To improve the gain of the reflectarrays, it is required that the reflection phase errors on the reflectarray surface be minimized. For this purpose, sufficiently wide reflection phase range and low phase sensitivity should be realized with the designed element. For bandwidth improvement, the reflection phase of the element should be linear with the frequency variation. In this paper, various researches to improve the reflection phase characteristics of the element for high gain and broadband reflectarrays, such as multi-layer and single-layer multi-resonant structures, are reviewed. Also, dual-reflectarray configuration for compact antenna design is reviewed. Finally, various applications of reflectarrays such as contoured beam, near-field focusing, and RCS reduction are reviewed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.4
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• pp.342-349
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• 2016

We design a displaced-axis Gregorian dual antenna in the form of a metal reflectarray antenna for millimeter wave region, W-band. Unlike a reflectarray composed of printed patch antennas on a dielectric substrate, metallic rectangular waveguide unit-cells are proposed to avoid the loss of substrate and take an advantage of ease of typical metal machining fabrication. In this paper, the radiation characteristics of constructed metal reflectarray antennas show ultra high-gain antenna over 50 dBi at a target frequency in W-band. The experimental measurements are conducted in millimeter-wave compact range antenna measurement system.

• Journal of IKEEE
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• v.28 no.1
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• pp.20-25
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• 2024

This paper presents a new dualband shared-aperture microstrip antenna to operate in the S-Band of 2 GHz and X-Band of 8 GHz, for a Low Earth Orbit satellite antenna system. The proposed antenna incorporates two types of patches those are a rectangular loop-shaped for the S-Band and a square patch for the X-Band. Each patch are optimized for its respective operating band with minimal interference. The proposed antenna achieves a bandwidth of 16 MHz in the S-Band and 572 MHz in the X-Band. The highest gain is measured 7.14 dBi at 1.99 GHz and 7.95 dBi at 7.88 GHz. The proposed antenna exhibits half power beamwidths of 85 degree and 80 degree at 1.99 GHz and 7.88 GHz, respectively. The proposed dualband shared-aperture microstrip antenna may be a good candidate for as a feeding system of a dualband reflectarray antenna With its unidirectional radiation pattern from excellent agreement between simulation and measurement results.

• Proceedings of the Korea Contents Association Conference
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• 2014.06a
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• pp.35-36
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• 2014