• ETRI Journal
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• v.41 no.2
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• pp.167-175
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• 2019

A wideband dual-polarized antenna coupling cross resonator is proposed for LTE700/GSM850/GSM900 base stations. An additional resonance is introduced to obtain strong coupling between the dipole and resonator. Moreover, the input impedance of the proposed antenna is steadily close to $50{\Omega}$, which results in better impedance matching. Therefore, a wide bandwidth can be achieved with multiresonance. A prototype is fabricated to verify the proposed design. The measured results show that the antenna has a fractional bandwidth of 35.7% from 690 MHz to 990 MHz for ${\mid}S_{11}{\mid}$ < -15 dB. Stable radiation patterns as well as gain are also obtained over the entire operating band. Moreover, a five-element antenna array with an electrical downtilt of $0^{\circ}$to $14^{\circ}$ is developed for modern base station applications. Measurement shows that a wide impedance bandwidth of 34.7% (690 MHz to 980 MHz), stable HPBW (3-dB beamwidth) of $65{\pm}5^{\circ}$, and high gain of $13.8{\pm}0.6dBi$ are achieved with electrical downtilts of $0^{\circ}$, $7^{\circ}$, and $14^{\circ}$.

• Journal of electromagnetic engineering and science
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• v.15 no.4
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• pp.239-244
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• 2015

A simple planar heptaband antenna with a coupling feed for 4G mobile applications is proposed. This antenna consists of a folded monopole and a feed strip line on the top plane and an L-shaped line with a coupling plate on the bottom plane. The antenna provides a wide bandwidth to cover the LTE/GSM/UMTS heptaband operation. The measured 6-dB return loss bandwidth is 152 MHz (820-972 MHz) in the lowfrequency band and 1,150 MHz (1,600-2,750 MHz) in the high-frequency band. The overall dimensions of the proposed antenna are $60mm{\times}105mm{\times}1.2mm$.

• Proceedings of the KAIS Fall Conference
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• 2008.05a
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• pp.115-117
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• 2008

본 논문에서는 Dual Band Microstrip Patch 안테나를 제작하였다. 성능 측정을 위해서 슬릿의 위치에 따른 특성을 Ansoft사의 HFSS를 이용하여 시뮬레이션하였고, 이를 바탕으로 GSM과 DCS 주파수 대역을 동시에 만족 시키는 원형 패치 안테나를 인셋(inset) 급전 방식을 이용하여 원하는 중심 주파수에서 공진이 일어나도록 설계 하였다. 그 결과 슬릿과 패치의 간격이 0.5mm, 슬릿의 폭은 1mm, 각도는 $98^{\circ}$일 때 가장 좋은 특성과 각각의 중심주파수에서 $S_{11}$이 -6.85dB, -9.691dB인 결과를 얻을 수 있었다.

• 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 Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.249-254
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• 2005

This paper presents the design of a novel small and wide band planar inverted F-antenna which simultaneously covers GSM900/GPS/DCS1800/DCS1900/DMB service. The proposed antenna consisting of a main patch with rectangular slit, strip 1 and strip 2, occupied the total volume of.$15\times36\times6mm^3$. A very wide impedance bandwidth characteristic was achieved by optimizing both the distance between the feed line and short strip and the length of rectangular slit on the main patch. The commercial electromagnetic software, CST Microwave Studio, is used to design the structure. The maximum gains at the frequencies of 900, 1575, 1800, 1900, and 2600 MHz were 2.07, 1.07, 1.69 and 0.55, -1.99 dBi, respectively. The overall shape of the radiation patterns is suitable for mobile communication application.

• Journal of information and communication convergence engineering
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• v.13 no.4
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• pp.235-240
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• 2015

A decimation chain for multi-standard reconfigurable radios is presented for 900-MHz and 1,900-MHz dual-band cellular standards with a data interpolator based on the Lagrange method for adjusting the variable data rate to a fixed data rate appropriate for each standard. The two proposed configurations are analyzed and compared to provide insight into aliasing and the signal bandwidth by means of a newly introduced measure called interpolation error. The average interpolation error is reduced as the ratio of the sampling frequency to the signal BW is increased. The decimation chain and the multi-rate analog-to-digital converter are simulated to compute the interpolation error and the output signal-to-noise ratio. Further, a method to operate the above-mentioned chain under a compressed mode of operation is proposed in order to guarantee continuous packet connectivity for inter-radio-access technologies. The presented decimation chain can be applied to LTE, WCDMA, GSM multi-mode multi-band digital front-end which will ultimately lead to the software-defined radio.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.8
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• pp.745-753
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• 2011

In this paper, the planar monopole antenna for multi-band service is proposed. The proposed antenna, which is a rectangular patch antenna with a U-shaped slit based on a monopole antenna for wide bandwidth characteristic, is designed and analyzed. The antenna size has been miniaturized by using the U-shaped slit. The frequency characteristics are modified and optimized by varying specific parameters. To obtain desired frequency bands, the U-shaped slit and patch lines have been applied. Whole antenna dimensions including the ground plane are $35{\times}50{\times}1\;mm^3$, and the antenna part size is $35{\times}27\;mm^2$. It is fabricated on the FR-4 substrate(${\epsilon}_r=4.4$) using a microstrip line of $50{\Omega}$ for impedance matching. For the measured results, the impedance bandwidth below a VSWR of 2 is 790~916 MHz, 1.74~2.14 GHz, and 2.36~3.13 GHz. The fabricated antenna is satisfied with the aimed impedance bandwidth in GSM/DCS/US-PCS/UMTS/Bluetooth/S-DMB applications.

• Journal of IKEEE
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• v.17 no.4
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• pp.484-491
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• 2013

In this paper, we proposed an internal multiband loop embedded monopole antenna for mobile handset that could be used for smart phones. The proposed antenna has a volume of 40 mm(W) ${\times}$ 15 mm(L) ${\times}$ 5 mm(H), ground plane size is 40 mm(W) ${\times}$ 80 mm(L), and covers the GSM900 (Global System for Mobile communications : 880-960 MHz), K-PCS (Korea-Personal Communications Service : 1750-1870 MHz), US-PCS (US Personal Communications Service : 1850-1990 MHz), WCDMA (Wideband Code Division Multiple Access : 1920-2170 MHz), Wibro (2300-2390 MHz), Bluetooth (2400-2483 MHz) and WLAN (Wireless Local Area Network : 2400-2483.5 MHz) bands for VSWR (voltage standing wave ration) less than 3. The proposed loop adding design at middle section of longest branch showed wide impedance bandwidth for the lowest resonance frequency band. The proposed antenna have a lowest resonance frequency band from 738 MHz to 1075 MHz for S11 value of -6dB. A HFSS (High Frequency Structure Simulator) of the Ansys Corporation based on a finite element method is employed to analyze the proposed antenna in the design process and to compare the simulation and experimental results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.9
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• pp.833-839
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• 2011

This paper has suggested a technique for measuring VSWR at 1.8 GHz band for various modulated signals. By using directional coupler the power of incident and reflected wave is measured, and in order to minimize the size and cost of the measuring circuit, a SPDT(Single Pole Double Throw) switch is adopted to realize the circuit with just one detector and one A/D(Analog to Digital) converter. MCU(Micro Control Unit) is used to calculate the voltage reflection coefficient and VSWR, and the measured VSWR error has improved by approximately 0.2 with applying a simple bubble sorting algorithm to reduce the measurement error, the MCU process time and load.

• Journal of electromagnetic engineering and science
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• v.9 no.1
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• pp.25-31
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• 2009

This paper describes CMOS VCO circuit design procedures and techniques for multi-band/multi-standard RF transceivers. The proposed techniques enable a 4 GHz CMOS VCO to satisfy all requirements for Quad-band GSMIEDGE and WCDMA standards by achieving a good trade-off among important specifications, phase noise, power consumption, modulation performance, and chip area efficiency. To meet the very stringent GSM T/Rx phase noise and wide frequency range specifications, the VCO utilizes bond-wire inductors with high-quality factor, an 8-bit coarse tune capbank for low VCO gain(30$\sim$50 MHz/V) and an on-chip $2^{nd}$ harmonic noise filter. The proposed VCO is implemented in $0.13{\mu}m$ CMOS technology. The measured tuning range is about 34 %(3.17 to 4.49 GHz). The VCO exhibits a phase noise of -123 dBc/Hz at 400 kHz offset and -145 dBc/Hz at 3 MHz offset from a 900 MHz carrier after LO chain. The calculated figure of merit(FOM) is -183.5 dBc/Hz at 3 MHz offset. This fully integrated VCO occupies $0.45{\times}0.9\;mm^2$.