• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.2
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• pp.208-216
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• 2002

In this paper, the design method of a waveguide broad-wall longitudinal slot array monopulse antenna of X-type monopulse axes is presented, and the method is verified through manufacture and measurement. In the antenna design of this paper, the antenna size is small and the monopulse axes are X-type. Thus, the common continuous aperture distribution fuction is not suitable and the power balance among antenna quadrants should be considered. Also, since the waveguide height is reduced into 0.1 wavelength, the modelling of the slot characteristics is not simple. Thus, in this paper, the aperture distribution is optimized by using random number, and the balance among the quadrants is achieved by applying the quadrant weighting factor during the aperture optimization process. Also, the moment method procedure is accelerated by applying the interpolation technique to some part of the moment matrix, and the moment method procedure is added to the array synthesis program as a subroutine so that the slot characteristics can be calculated directly when it is required. Based on this method, a antenna of 28dBi is designed and manufactured. It is found that the antenna characteristics is similar to design data.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.71-72
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• 2013

In this paper, a design method for a compact slot antenna for 5.8 GHz RFID band (5.725-5.875 GHz) is studied. The proposed slot antenna is size-reduced by bending both ends of the straight slot in "${\Gamma}$"-shape, and a rectangular feed patch is located inside the slot. The effects of slot length, location of feed patch, and width and length of feed patch on the antenna performance are examined. A prototype antenna with optimized parameters for 5.8 GHz band is fabricated on an FR4 substrate and tested experimentally. The experimental results show that the frequency band for a VSWR < 3 ranges 5.72-6.13 GHz (bandwidth 410 MHz), and it corresponds fairly well with the simulated band 5.64-5.97 GHz (bandwidth 330 MHz). The fabricated antenna shows good radiation performance such as maximum power density in both directions normal to the slot plane, and low cross-polarization level of < -20 dB.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.12
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• pp.2763-2768
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• 2013

In this paper, a design method for a compact slot antenna for 5.8 GHz RFID band (5.725-5.875 GHz) is studied. The proposed slot antenna is size-reduced by bending both ends of the straight slot in "I"-shape, and a rectangular feed patch is located inside the slot. The effects of slot length, location of feed patch, and width and length of feed patch on the antenna performance are examined. A prototype antenna with optimized parameters for 5.8 GHz band is fabricated on an FR4 substrate and tested experimentally to verify the results of this study. The experimental results show that the frequency band for a VSWR < 3 ranges 5.72-6.13 GHz (bandwidth 410 MHz), and it corresponds fairly well with the simulated band 5.64-5.97 GHz (bandwidth 330 MHz). The fabricated antenna shows good radiation performance such as maximum power density in both directions normal to the slot plane, low cross-polarization level of < -20 dB, and realized gain > 0 dBi within the frequency band.

• Journal of Advanced Navigation Technology
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• v.17 no.5
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• pp.491-496
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• 2013

In this paper, a half-wavelength folded-slot antenna, which can be applied to RF module for 3G mobile communications by which security lights are monitored and controlled, is proposed. The proposed antenna can be regarded as modified folded-slot structure which has the size reduced to a half of conventional ${\lambda}g$ folded-slot antenna and can be placed at the ground plane edge. In spite of that, the proposed antenna still maintain the advantage of conventional folded-slot antenna that input impedance is close to $50{\Omega}$. The antenna is designed and fabricated within the upper space of $40.5{\times}10mm^2$ on $40.5{\times}62mm^2$ substrate for 3G mobile communication frequency band. The measured impedance bandwidth and antenna gain are 390 MHz and 2 dBi respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.5 s.96
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• pp.501-510
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• 2005

In this paper, the miniaturized linear and circular polarization microstrip antennas are designed and fabricated at the resonant frequency of 1.575 GHz. To miniaturize the microstrip patch antenna(MPA), the 'L' type plates are attached under the rectangular microstrip patch. In case of the linear polarization, the size of the microstrip antenna attached the 14 plates is reduced to $67.9\%(47mm{\times}47mm)$ compared with general $MPA(83mm{\times}83mm)$. The return loss and -10 dB bandwidth are -34.4 dB and 49 $MHz(3.1\%)$. And the radiation pattern is broad through the size reduction of the patch. Also in case of the circular polarization, the size of the microstrip antenna with 13 plates is reduced to $54.6\%(53mm{\times}54mm)$ compared with the general $MPA(76mm{\times}83mm)$. The axial ratio is 1.37dB at 1.575 GHz, the 2 dB axial ratio bandwidth is 14 $MHz(0.8\%)$. As that result, we could confirm that 3-dimensional structure with attached 'L' shaped plate is proper form for the miniaturization of linear and circular polarization microstrip antenna.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.5
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• pp.249-254
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• 2014

In this paper, minimizing of a parabolic edge planar monopole antenna by scaling method is presented. With the aid of a matching step and discontinuous CPW, the antenna easily adjusts the impedance matching. We used an FR4 dielectric substrate with a dielectric constant of 4.4. The dimensions of the antenna are $26mm{\times}31mm{\times}1.6mm$. A return loss value of more than 10dB was found in the 2.37GHz to 10.52GHz (8.15GHz) range of the antenna fed by the discontinuous CPW. The radiation pattern is about the same as that of the dipole antenna at all frequencies. Configuration elements of the antenna except feed part were reduced into the same rate. So, the size of the antenna was decreased and a broadband property was maintained. Therefore, the self-complementary characteristic of the antenna was confirmed. While satisfying the UWB band, having the smallest size in the antenna miniaturized by scaling;when scale was 0.6. The dimensions of the antenna are $15.6mm{\times}18.6mm{\times}1.6mm$. The return loss was more than 10 dB of the measured result in the range of 3.07GHz to 12.59GHz (9.52GHz).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.939-940
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• 2015

In this paper, a design method for a quasi-Yagi antenna (QYA) suitable for UHF band is studied. Due to the mutual coupling between a coplanar strip (CPS)-fed planar dipole and a conducting strip director placed close to the dipole, the dipole obtains broadband characteristics. A ground reflector improves gain in the lower frequency band, and the antenna size might be reduced by employing a bent reflector. The balun between the CPS line and the microstrip(MS) line is constructed by connecting the end of MS line and the CPS line through a shorting pin. In addition, a ring-type conductor connects the CPS line and reflector. The effects of various geometrical parameters and balun on the antenna characteristics are examined. An antenna, as an design example for the proposed antenna, is designed for the operation in the frequency band of 470-806 MHz for terrestrial DTV.

• 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.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.5 s.120
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• pp.563-568
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• 2007

In this paper, the proposed package antenna, which is meander line structure with short pin, is miniaturized to realize RF-SoP at 900 MHz RFID band. The RFID BGA(Ball Grid Array) chip is put in a cavity of LTCC Layers. The coupling and cross talk, which are happen between BGA chip and proposed package antenna, are reduced by faraday cage, which consists of ground and via fences, is realized to enhance the isolation between BGA chip and antenna. The proposed antenna structure is focused on the package level antenna realization at low frequency band. The novel proposed package antenna size is $13mm{\times}9mm{\times}3.51mm$. The measured resonance frequency is 0.893 GHz. The impedance bandwidth is 9 MHz. The maximum gain of radiation pattern is -2.36 dBi.

• Journal of Advanced Navigation Technology
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• v.27 no.5
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• pp.629-634
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• 2023

In this paper, the design of a miniaturized wideband tapered slot antenna using slots combining various types of fan-shaped structures was studied. To miniaturize the tapered slot antenna and make it operate at low frequencies, slots combining fan-shaped structures were added to the ground plane of the tapered slot antenna. The miniaturization design process of the final proposed antenna was systematically explained by comparing the input reflection coefficient and gain variations when each fan-shaped structure was appended, compared to when there was no slot. The proposed miniaturized wideband tapered slot antenna using slots combining the fan-shaped structures was fabricated on an RF-35 substrate and its measured characteristics were compared with the simulation results. Experiment results show that the frequency band with a voltage standing wave ratio (VSWR) less than 2 was 2.59-11.39 GHz, and gain within the band was measured to be 3.3-7.0 dBi. The proposed miniaturized wideband tapered slot antenna can be reduced in size by 36.9%, compared to when there are no slots in the ground plane.