• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.7
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• pp.1459-1467
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• 1997

The current on the thin planar structure as an element of the transversely fed electromagnetically coupled(EMC) microstrip dipole array antenna is obtained by using the integral forms of the finite difference time domain(FDTD) method. This method was applied to calculating the optimum current distribution (Doplh-Tchebyscheff distribution) of each dipole element on the feed line as a function of their offset positions for the narrow main beam width and the side beam level below -20 dB. The current on each dipole substitutes for the electric and magnetic current densities on the virtual surface of the FDTD calculation to express the far field intensity, the calculation time and the computer memeory can be reduced to about 80% and 1.3 Mbyte, respectively. The calculated radiation patterns are compared to the measured values and these are in good agreement.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.5
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• pp.738-746
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• 1999

In this paper, a microstrip $18\times2$ dual beam array antenna is designed at 10 GHz. The radiating element is an aperture-coupled patch, and it is analyzed by the transmission line model. The feed is a tapered parallel-series type to reduce the side lobe level. To obtain dual beam at $\pm45^{\circ}$, The difference in phase excitation between the elements is $180^{\circ}$. In conclusion, the side lobe level is 25 dB, and the beam width $8^{\circ}$with two main lobes at $\pm44.5^{\circ}$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.8
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• pp.886-892
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• 2010

In this paper, the hybrid antenna utilizing epsilon negative zeroth-order resonance(ENG ZOR) and $TM_{010}$-mode is presented. The antenna has a directional radiation pattern and improved bandwidth. To obtain a ENG ZOR and $TM_{010}$-mode, the hybrid antenna employs the mushroom structure and the microstrip patch, respectively. Two antennas of the mushroom and the patch are coupled by gap and fed by one coaxial feed. The frequencies of ENG ZOR and of $TM_{010}$ resonance are designed to be 4 GHz and 3.9 GHz, respectively. Because two resonant frequencies are set to be close, the dual-resonance can be formed, resulting in the broader bandwidth. Even though the radiation pattern of an ENG ZOR antenna is omnidirectional, the directional radiation of a microstrip patch antenna compensates the null of omnidirectional pattern of an ENG ZOR antenna. Thus, the hybrid antenna has a directional radiation pattern. The antennas having 4, 3, and 2 unit cells of mushroom structure are designed and analyzed. The antennas have fractional bandwidths of 4.29~4.95 %, gains of 3.16~5.57 dBi, and radiation efficiencies of 62.4~94.2 %.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.6
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• pp.706-713
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• 2010

In this paper, the small loop antenna with a parasitic loop structure for penta-band mobile phone application is proposed. This antenna is composed of a feed monopole, a radiating loop antenna with a parasitic loop structure and an additional radiating element. The antenna is printed on the very thin flexible substrate to mount on the dielectric carrier with a volume of 40 mm$\times$11 mm$\times$3 mm. The bandwidth of the proposed antenna is 402 MHz(773~1,175 MHz) for low band and 583 MHz(1,622~2,205 MHz) for high band. As a result, the proposed antenna covers the five bands of GSM850, GSM900, DCS1800, PCS1,900 and WCDMA for a 3:1 VSWR. Moreover, the radiation pattern, gain and efficiency are appropriate for mobile handset. Therefore, this antenna is suitable for small sized multi-band mobile handset applications.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.9
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• pp.896-905
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• 2004

In this paper, the design, fabrication and experiment on a planar array antenna with a flat-topped radiation pattern for a mobile base station antenna were described. The current distribution of an antenna aperture, which is easily realizable in a feeding network compared with the conventional one of sin(x)/x was optimized for shaping a desired flat-topped radiation pattern. The planar array antenna designed in this paper has a rectangular lattice and is composed of array elements of 16${\times}$8. Each radiating element, which is a microstrip element fed coaxially, has a linear vertical polarization and the feed network which use a Wilkinson power divider and a 180$^{\circ}$ ring hybrid coupler as a base element is designed. The flat-topped radiation pattern with 90$^{\circ}$ is shaped by 16 array elements with the element spacing of 0.55 λ$_{ο}$ in the azimuth plane, and the normal radiation pattern with 10$^{\circ}$ is shaped by 8 array elements with the element spacing of 0.65 λ$_{ο}$ in the elevation plane. Also, the planar array antenna is symmetrically divided into four parts. It consists of one hundred-twenty-eight radiating elements, thirty-two 1-4 column dividers, low 1-8 row dividers and one 1-4 input power divider. In order to verify electrical performances of the planar way antenna proposed in this paper, the experimental breadboard operated in tile band of 1.92～2.17 GHz(IMT2000 band) was fabricated, and its experimental results were a good agreement with simulation ones.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.3074-3078
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• 2014

We implemented a dual-band slot-coupled patch (SCP) antenna for the external access point (AP) of the wireless local area network (WLAN) band. The antennas consist of two radiators on three layers. The first radiator is a slotted bow tie antenna operating at the 2.4-2.483 GHz band. The second radiator is a patch antenna with parasitic elements operating at 4.095-5.845 GHz. The high gain and broad bandwidth is important element of wireless access. To enhance the bandwidth, a coupled feeding was used in the first radiator and a parasitic patch was used in the second radiator. We used a parasitic patch and chock to improve the directivity and isolation in both radiators. The porposed antenna was designed by EM simulation tool and measured. The S11 of the antenna was less than -11dB (VSWR 1.8:1) at operating frequency. The peak gain was more than 6 dBi in the first antenna and more than 8 dBi in the second antenna.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.6
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• pp.47-53
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• 2023

In this paper, We designed a waveguide-type feed structure that converts millimeter wave dual-polarized signals into monopulse signals and presented a manufacturing method. At millimeter-wave such as the W band, the size of the waveguide is very small, making it very difficult to manufacture complex structures. Therefore, because manufacturability is important for the waveguide-type feed structure in the millimeter-wave, electro forming and diffusion bonding were proposed and verified in this study. The designed monopulse feed structure consists of eight 180° hybrids that combine 90° hybrids and self-compensating phase shifters, and four OMTs to separate dual polarization. The designed feed structure was designed to facilitate electro forming and diffusion bonding, and the manufactured feed structure was verified through a network analyzer. It was confirmed that the two proposed production methods produce a monopulse signal well through the measured magnitude and phase of the port.

• JSTS:Journal of Semiconductor Technology and Science
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• v.6 no.3
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• pp.169-174
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• 2006

In this work, we demonstrate a novel compact mechanical beam steering transmitter based on a direct vertical integration of a 2-D MEMS-based mechanical beam steering antenna with a VCO on a single silicon platform. By eliminating the long feed lines and waveguide metal blocks, the radiation pattern has been improved vastly, resulting in an almost ideal pattern at every scan angle. The losses incurred by the feed lines and phase shifters are also eliminated, which allows the transmitter to be implemented using only a single VCO. The system complexity has been greatly reduced with a total module size of only 1.5 cm ${\times}$ 1.5 cm ${\times}$ 0.4 cm. This work demonstrates that RF MEMS can be a key enabling technology for high-level integration.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.7 no.4
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• pp.188-194
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• 2014

In this paper, an antenna which has quad band in LTE (0.746 ~ 0.798 GHz), GSM(0.824 ~ 0.960 GHz), DCS(1.71 ~ 1.88 GHz), WCDMA(1.91 ~ 2.17 GHz) is proposed. An antenna size is $122mm{\times}50mm{\times}0.8mm$ on FR4(${\epsilon}_r=4.4$) ground substrate. In the proposed antenna, branch line is applied to the conventional PIFA architecture to achieve multi-bandwidth. Coupling power supply is applied for a wide bandwidth. Result of the measurement is as follows. When the low frequency, the antenna presents gain of 0.93 ~ 1.92dBi, and radiation efficiency of 49.60 ~ 76.35 %, and When the high frequency, gain is 2.19 ~ 4.66dBi, and radiation efficiency is 60.40 ~ 80.01 %, and with a VSWR < 2 (${\leq}-10dB$)measurement results for standard satisfies all band. Judging from the result, proposed multiband antenna is expected to be applied. B4G mobile terminals since the antenna shows an outstanding performance.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.395-398
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• 1998

In this paper, the design, fabrication, and experiments of linearly tapered slot antenna(LTSA) with uniplanar microstrip-to-coplanar strip(CPS) line transitions are presented. The effect of reducing and increasing with taper width G teper longth 1, and opening angle are also mesured at 10 GHz.