• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.3 s.357
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• pp.105-110
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• 2007

We have built the millimeter-wave passive imaging system with a lens and mechanical scan antenna. The lens was designed based on optical theory in order to focus millimeter-wane. A full image was taken from image points scanned by Placing antenna at the representative focal plane selectively. An integrated antenna array device for low-loss and low-noise with the array of 4 by 1, where components such as antenna, balun, MMIC, and detector were assembled on a sin91e substrate, and a fermi tapered slot antenna with high-gain and low-side lobe were used for elements of this millimeter-wave passive imaging system. Two dimensional antenna arrangement on focal plane was achieved in this imaging system.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.5
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• pp.209-215
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• 2017

In this paper, an antenna having 2-axes cross monopulse for Ka band millimeter-wave seeker is designed and antenna performance is verified through vacuum-brazing method for fabrication and measurement. Also, by designing and manufacturing a waveguide circulator the antenna including the circulator is measured. Radiating part of the antenna takes optimized slot lengths and offsets from Elliot's array synthesis procedure using the generic algorithm and feeding part for cross monopulse axes uses the folded waveguide to optimize the S-parameter result. Based on this method, the antenna has 33.3 dBi gain, $3.5^{\circ}{\pm}0.5^{\circ}$ beamwidth, below -23 dB SLL through fabricating and measuring. It is found that antenna characteristics is similar to design results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.10
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• pp.1071-1078
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• 2003

In this paper, the planar, compact, and broadband phased array antenna system for IMT-2000 applications has been investigated. Two methods far designing a low-cost and low-complex beam-farming network are proposed. First, a new compact and broadband phase shifter with continuously controlled phase bits is designed by using parallel coupled lines. Second, its equivalent phase delay line is suggested to be capable of replacing the complex phase shifter with a reference phase bit on a phased array antenna. For the purpose of achieving the broadband system, in addition to the broadband phase shifter, a wide-slot antenna with a ground reflector is utilized as an element antenna. Therefore, the phased array antenna system has achieved compact size, broad bandwidth, and wide steering angle, although it has low complexity and low fabrication cost. The 3${\times}$1 phased array antenna system has a compact size of 1.6 λ${\times}$ l.6 λ, which is the sufficient ground plane of the wide-slot antenna. Experimental results present that the S$\_$11/ has less than 15 dB within the band and its radiation patterns on an E-plane have the capability of steering an antenna beam from -29$^{\circ}$to +30$^{\circ}$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.30 no.1
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• pp.45-53
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• 2019

In this paper, three types of array antennas for 5G mobile devices operating at 28 GHz were designed, and their performances were compared. The isolation between antenna elements was compared based on $S_{21}$. The $S_{21}$ of dipole, slot, and patch type are -13.76 dB, -16.88 dB, and -11.47 dB, respectively, with the slot-type antenna having the highest isolation. In order to compare the beam coverage performance, several characteristics such as beam width and maximum beam steering angle were analyzed. The analysis shows that the slot type has the widest steering angle of $63^{\circ}$ while the patch type has narrowest with $36^{\circ}$. In addition, to verify the performance of the antennas in the actual usage environment of the device, antenna characteristics in talk mode and data mode were analyzed through simulation. The results confirmed that the slot-type array antenna is the most suitable array antenna element for 28 GHz 5G mobile devices.

• Journal of Satellite, Information and Communications
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• v.2 no.2
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• pp.10-15
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• 2007

Small size and low profile antenna for mobile vehicular-top-mounted is needed in satellite communication services such as DBS, Satellite Internet and VSAT. In middle latitudes, the development of an array antenna which has the conformal, low profile and 45 degree beam tilted configuration, and has the high gain with sharp beamwidth, low sidelobe and low loss is required for Ku-band satellite communication. In this paper, in order to meet with these performances, an array antenna consisting of the vertical polarized waveguide longitudinal slots based on the leaky-wave mode of traveling wave antenna is proposed. An array antenna consisting of 16 leaky-wave elements is showing 30 dBi of gain, 4.9 degree of beamwidth, below than -20 dB of sidelobe level, 45 degree of beam tilt angle in center frequency. Feed network designed by waveguide cooperated feed shows good performance of wideband and low loss.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.3 s.94
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• pp.311-318
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• 2005

Periodically perforated slot structure in the upper wall of the parallel plate waveguide is analyzed with main interest focusing on the diffraction Properties. The Periodic slot array is of infinite extent in one direction and of finite extent in the other direction. Various numerical results for reflection from the slotted section and transmission beyond the slotted section, and the radiation through the slotted section into the upper half space are presented with the height of feeding parallel plate waveguide, single slot size, and the periodicity between slots as parameters. This study is thought to be helpful to the design of the ventilation hole in the TFT-LCD and PDP.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.3
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• pp.273-279
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• 2009

In this paper, an antenna which has dipole-like radiation pattern and low profile is proposed. The antenna is composed of four elements slot array based on L-shaped 0.43 $\lambda_g$ slot element. It presents a omni-directional radiation patter in the azimuth plane and has a null toward broad-side direction. In the design, a small mono-pole antenna which acts as a large capacitance element, combined with the partially removed ground plane by four L-shaped slots. As a result, these structure act as a LC resonator for radiation. The measured result shows, the impedance bandwidth(VSWR$\leq$2) of the proposed antenna is 60 MHz(2.35$\sim$2.41 GHz). The measured maximum radiation gain and efficiency of proposed antenna is 0.02 dBi, 56.7 % at center frequency 2.38 GHz, respectively. The proposed antenna can be applied to wireless tan access point system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.5
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• pp.484-491
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• 2013

In this paper, the method of designing a wideband antenna has been introduced through the design technique that simultaneously employs L- and slot-type feeds. Using the two kinds of feeds and additional fence structure, a compact wideband patch antenna has been realized. The size of the patch has been reduced by about 30 % based on the low frequency(824 MHz) and the full fractional bandwidth is wider than 100 %. The L-feed element is for the EM coupling feeding at the low frequency, while it functions as a feeding line for the power coupling through the slot at the high frequency. The proposed antenna has been designed not only for wideband operations but also for a proper array element with a reduced size. Thus, the foundation for developing the ultra wideband patch array antennas has been prepared. The fabricated antenna has been found to have good characteristics on V.S.W.R and the radiation patterns over the full bands. The experimental and computed results are shown to be in good agreement.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.683-688
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• 2018

Recently, the demand for electric energy has been increasing due to the spread of hybrid electric vehicles. In this study, to meet this demand, the ANSYS MAXWELL electromagnetic simulation system was used to compare the power generation characteristics of three types of suspension system that can generate electricity using energy harvesting technology. Next, the optimal design was determined for each model by using the commercial PIDO (Process Integration and Design Optimization) tool, PIANO (Process Integration, Automation and Optimization). We selected three design variables and constructed an approximate model based on the experimental design method through electromagnetic analysis for 18 experimental points derived from Orthogonal Arrays among the experimental design methods. Then, we determined the optimal design by applying the Evolutionary Algorithm. Finally, the optimal design results were verified by electromagnetic simulation of the optimum design result model using the same analysis conditions as those of the initial model. After comparing the power generation characteristics for the optimal structure for each linear generator model, the maximum power generation amounts in the 8pole-8slot, 12pole-12slot, and 16pole-16slot structures were 366.5W, 466.7W and 579.7W, respectively, and it was found that as the number of slots and poles increases, the power generation increases.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.4
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• pp.535-540
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• 2013

We design a slotted waveguide antenna for X-band which a 1.4m length with slot depth variation. A 54 slot array is modeled and simulated by CST, and the side lobe level is suppressed effectively in a certain range of frequency. The experimental results of the antenna show that its gain, maximum sidelobe level and half power beam-width are 21.8dB, -31dB and 2.0deg, respectively.