• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.6
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• pp.1265-1270
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• 2011

Different wireless technologies have been developed for various mobile applications. To offer seamless service in next mobile communication systems, it needs handoff service between heterogeneous mobile access networks. A high data rate handoff call from WLAN to cellular mobile network can increase rapidly the blocking probability of BS of cellular mobile network. To solve this problem, this paper proposes a new handoff scheme based on user service profiles. The performances of the proposed scheme are evaluated using computer simulations.

• Journal of information and communication convergence engineering
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• v.15 no.4
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• pp.199-204
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• 2017

A compact dual-band half-ring-shaped (HRS) bent slot antenna fed by a coplanar waveguide for wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications is presented. The antenna consists of two HRS slots with different lengths and widths. The two HRS slots are connected through an arc-shaped slit, and the upper HRS slot is bent in order to reduce the size of the antenna. The optimized dual-band HRS bent slot antenna operating in the 2.45 GHz WLAN and 3.5 GHz WiMAX bands is fabricated on an FR4 substrate with dimensions of 30 mm by 30 mm. The slot length of the proposed dual-band slot antenna is reduced by 35%, compared to a conventional dual-band rectangular slot antenna. Experimental results show that the proposed antenna operates in the frequency bands of 2.40-2.49 GHz and 3.39-3.72 GHz for a voltage standing wave ratio of less than 2, and measured gain is larger than 1.4 dBi in the two bands.

• JSTS:Journal of Semiconductor Technology and Science
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• v.7 no.2
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• pp.98-101
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• 2007

A fully integrated 5-GHz CMOS power amplifier for IEEE 802.11a WLAN applications is implemented using $0.18-{\mu}m$ CMOS technology. An on-chip transmission-line transformer is used for output matching network and voltage combining. Input balun, inter-stage matching components, output transmission line transformer and RF chokes are fully integrated in the designed amplifier so that no external components are required. The power amplifier occupies a total area of $1.7mm{\times}1.2mm$. At a 3.3-V supply voltage, the amplifier exhibits a 22.6-dBm output 1-dB compression point, 23.8-dBm saturated output power, 25-dB power gain. The measured power added efficiency (PAE) is 20.1 % at max. peak, 18.8% at P1dB. When 54 Mbps/64 QAM OFDM signal is applied, the PA delivers 12dBm of average power at the EVM of -25dB.

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.2
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• pp.280-285
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• 2015

A fully integrated high-efficiency linear CMOS power amplifier (PA) is developed for 802.11n WLAN applications using the 65-nm standard CMOS technology. The transformer topology is investigated to obtain a high-efficiency and high-linearity performance. By adopting a 2:2 output transformer, an optimum impedance is provided to the PA core. Besides, a LC harmonic control block is added to reduce the AM-to-AM/AM-to-PM distortions. The CMOS PA produces a saturated power of 26.1 dBm with a peak power-added efficiency (PAE) of 38.2%. The PA is tested using an 802.11n signal, and it satisfies the stringent error vector magnitude (EVM) and mask requirements. It achieves -28-dB EVM at an output power of 18.6 dBm with a PAE of 14.7%.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.7
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• pp.987-994
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• 2013

In this paper, a dual-band open-ended circular ring moNopole antenna for WLAN(Wireless Local Area Networks) applications. The proposed antenna is based on a planar moNopole design, and composed of open-ended one circular ring of radiating patches for dual-band operation. To obtain the optimized parameters, we used the simulator, Ansoft's High Frequency Structure Simulator(HFSS) and found the parameters that effect antenna characteristics. Using the obtained parameters, the proposed antenna is fabricated. The fabricated antenna is measured at the operating frequencies(2.4-2.484 GHz, 5.15-5.825 GHz), and the return loss coefficient, gain, and radiation patterns are determined.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.617-620
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• 2003

In this paper, a monolithic VCO has been designed for Wireless Local Area Network(WLAN) applications. The differential form VCO is constructed using positive feedback with capacitor and phase shift for low phase noise performance. The VCO shows the phase noise of -92.725 dBc/Hz at an offset frequency of 10KHz and the tunning range of 5.822~6.154GHz.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.129-130
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• 2007

I/Q demodulator is designed using RC-CR quadrature divider with two balanced mixer for WLAN applications. The I/Q demodulator has low power dissipation, good I/Q mismatch, a good isolation and conversion loss. The measured results shows close agreement with the predicted performance.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.4
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• pp.811-817
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• 2014

In this paper, a design method for a dual-band monopole antenna operating in the bands of 2.45 GHz WLAN and UWB is studied. A monopole antenna operating in UWB band is first designed, and a slot is inserted on the monopole to operate in 2.45 GHz WLAN band. The optimized dual-band monopole antenna is fabricated on an FR4 substrate, and the experimental results show that the antenna has a dual-band characterisitc in WLAN and UWB bands with the frequency bands of 2.35-2.50 GHz and 2.99-11.82 GHz for a VSWR < 2. Measured gain is 1 dBi at 2.45 GHz, and ranges 1.5-4.6 dBi in the frequency band of 3.1-10.6 GHz.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.6
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• pp.1049-1056
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• 2017

In this paper, a microstrip-fed dual-band monopole antenna with two arc-shaped lines for WLAN(: Wireless Local Area Networks) applications was designed, fabricated and measured. The proposed antenna is based on a microstrip-fed structure, and composed of two arc-shaped lines and then designed in order to get dual band characteristics. We used the simulator, Ansoft's High Frequency Structure Simulator(: HFSS) and carried out simulation about parameters L2, L5, and with/without slit to get the optimized parameters. The proposed antenna is made of $13.0{\times}34.0{\times}1.0 mm^3$ and is fabricated on the permittivity 4.4 FR-4 substrate($12.0{\times}34.0{\times}1.0mm^3$). The experiment results are shown that the proposed antenna obtained the -10 dB impedance bandwidth 360 MHz (2.29~2.65 GHz) and 1,245 MHz (4.705~5.95 GHz) covering the WLAN bands. Also, the measured gain and radiation patterns characteristics of the proposed antenna are presented at required dual-band(2.4 GHz band/5.0 GHz band), respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.12
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• pp.1659-1665
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• 2019

In this paper, a novel design of a compact printed monopole antenna for wireless local area network (WLAN) applications is investigated. The radiator with a patch of different line width and step-shaped ground planes is used to reduce the antenna size. The size of the antenna is 16 × 17 × 1 ㎣ and is fabricated with a photolithography technique. The simulated and measured results agree well. The resonant frequency of the investigated antenna is about 5.2 GHz and can cover an impedance bandwidth of 1 GHz for the measurement result. In addition, we presented the measured radiation pattern, presented the gain and efficiency measured in the required WLAN 5 GHz frequency band (5.15-5.825 GHz), and confirmed that it can be used as a 5 GHz band WLAN antenna. The investigated antenna has a small size, light weight, low cost, omni-directional radiation pattern, high gain, and high efficiency.