• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.7
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• pp.709-720
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• 2014

In this paper, we studied miniaturization of LPDA(Log-Periodic Dipole Array) antenna used for VHF and UHF bands. To miniaturize the LPDA antenna, in this study, the radiation elements in a low frequency were changed into a triangular meander structure which has small current cancelation effect at feed part. For the triangular meander structure, an isosceles triangular and right triangular meander structures were proposed and the LPDA antennas were miniaturized by using the two meander structures. Also, the simulated and measured results were compared for the two miniaturized LPDA antennas. As a result, the isosceles triangular meander and right angle triangular meander structure applied LPDA antennas were reduced up to 60.5 % and 72.4 % compared a basic LPDA antenna, respectively. Consequently, we confirmed that the triangular meander structure is suitable for miniaturization of a LPDA antenna.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.5
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• pp.1270-1276
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• 2010

In this paper, Quad-Band small antenna for GSM850, GSM900, DCS1800, DCS1900 is designed and fabricated. The antenna achieved the size reduction of over 67.9 % than the conventional PIFA(Planar Inverted-F Antenna) by using a MD(Magneto-Dielectric) material. A simple feeding microstrip line is used to feed the antenna from a $50{\Omega}$ coaxial line, which is capacitively coupled to the grounded patch structure for broadband characteristics. The impedance bandwidth the proposed antenna shows good results as broadband characteristics of 1341 MHz (801 ~ 2142 MHz) in VSWR < 3 (${\leq}\;-6\;dB$) and the gain is -6.67 ~ 4.25 dBi in the operating frequency.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.2 no.2
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• pp.69-77
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• 2009

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 Ka 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. Especially, for the lower sidelobe level the radiation power control using a design method of the different slot width is proposed. An array antenna consisting of 32 leakywave elements is showing 34.4 dBi of gain, 3.6 degree of beamwidth, below than -25 dB of sidelobe level, 43 degree of beam tilt angle in center frequency 20.0 GHz. 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.14 no.1
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• pp.75-80
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• 2003

This paper presents novel compact circularly polarized(CP) operation of a annular ring slot antenna with a 45$^{\circ}$truncated in the patch and a cross-slot of unequal slot lengths. A simple configuration based on a cross-slot of unequal slot lengths on the annular ring patch is adopted to realize a small-size element antenna and used a proximity coupled feed method. Experimental results show that much wider impedance bandwidth of 7.74 % and axial ratio bandwidth of 1.9 % in GPS band(1.5 GHz).

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.4
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• pp.343-350
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• 2003

Circularly polarized-dual band antenna for GPS(Global Positioning System) and satellite radio system is developed and measured. Both circular polarization and overall antenna dimension reduction are achieved by placing a partially filled high-permittivity substrate under radiating edges. The bandwidth is also improved by choosing an optimal geometric configuration with a partially filled high permittivity substrate. The proposed antenna can be installed on moving vehicles or ships.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.4
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• pp.515-525
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• 1998

In this paper, for both transmission and reception with single antenna system of satellite communication, dual-frequency antennas which operate simultaneously at 12.5 GHz and at 14.25 GHz are designed, constructed and measured. Also by using dual feeding structure, the problems of single-fed dual-frequency antenna such as the separation of transmitting and receiving signals and single polarization, are solved. Microstrip patch as a radiation element of dual-fed dual-frequency antenna has width and length which are the resonance lengths of the corresponding frequencies for transmission and reception, respectively. The effects of the feed line on the other frequency feeding are minimized with the optimal matching scheme for the feed lines. For solving the space problems of dual-fed two-dimensional array antennas, microstrip-line and coaxial probe feedings are used for each frequency and a two-dimensional $2\times2$ array antenna was designed and measured their characteristics. The experimental results show that errors of resonance frequencies are less than 1.44%, the return losses are less than -21 dB and the isolations between two feeding ports are less than -21 dB. The characteristics of radiation patterns of dual frequency microstrip antenna are measured and evaluated. The directivities, sidelobe levels and cross polarizations are also measured and compared with the simulations. The results show some errors due to the misalignment of coaxial probe feeding.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.2
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• pp.131-139
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• 2011

In this paper, we propose a double-faced window printed antenna for aircraft applications. The proposed antenna structure consists of a feeding line and a multi-loop radiator located on different sides of the window to use the limited given-area effectively. The proposed antenna is optimized by the genetic algorithm in conjunction with the FEKO EM simulator. The optimized antenna is built and installed on a 1/10 sized KUH-Surion mock-up and antenna performances such as the reflection coefficient and the radiation patterns are measured. The optimized antenna shows a half power matching bandwidth of about 33 % at 60 MHz and an average bore-sight gain of about -3.49 dBi. To verify the reception capability of the optimized antenna, we simulated the received power according to a flight scenario. The result confirms that the optimized antenna shows a minimum received power level above -60 dBm at a range of 200 km, which is similar to the pole antenna that is currently used as a FM voice antenna for KUH-Surion.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.10
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• pp.1269-1274
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• 2019

The paper presents a design of simple four-element microstrip-patch array antenna that is suitable for 5G applications. The proposed array consists of four rectangular microstrip patch elements with semicircular etches made on both sides of each elements. The antenna is fed using the combination of series and corporate feeding networks. The size of the ground is also changed to improve the antenna frequency. Finally, yagi elements are also added to improve the directive gain of the antenna. The presented microstrip patch array is able to achieve wide frequency bandwidth of 21.95-31.86 GHz. The antenna has also attained gain of 9.7 dB at 28 GHz and has maintained high gain and high directivity throughout the frequency band. The proposed array antenna fed by series-corporate feeding network, with low profile and simple structure is a good candidate for 5G applications.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.8
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• pp.42-50
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• 2007

This paper presents design methods for dual-frequency(2.4/5.8GHz) active receiving antennas. The proposed active receiving antennas are designed to interconnect the output port of a wideband antenna to the input port of an active device of High Electron Mobility Transistor directly and to receive RF signals of 2.4GHz and 5.2GHz simultaneously where the impedance matching conditions are optimized by adjusting the length of $1/20{\lambda}_0$(@5.8GHz) CPW transmission line in the planar antenna The bandwidth of implemented dual-frequency active receiving antennas is measured in the range of 2.0GHz to 3.1GHz and 5.25GHz to 5.9GHz. Gains are measured of 17.0dB at 2.4GHz and 15.0dB at 5.2GHz. The measured noise figure is 1.5dB at operating frequencies.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.4
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• pp.165-169
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• 2011

In recent years mobile phone handset terminal has tended to have additional various functions and slim and light weight, and its internal space is getting smaller and narrower. According to complex parts, small and narrow inner space is caused not sufficient bandwidth and lower impedance. Moreover, additional polarization loss by the surrounding parts produces is lower effectiveness and increases difficulties for getting the antenna gain. For IFA is low profile structure based on the ILA(Inverted L Antenna) which is transformed from the monopole antenna. While this antenna has lots of advantages in internal antenna of mobile phone, it has some disadvantage of reduced bandwidth and gains compared with monopole antenna. In this paper, propose vlade hybrid antenna use for the coupling structure.