• The Bulletin of The Korean Astronomical Society
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• v.24 no.1
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• pp.50-50
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• 1999

• ETRI Journal
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• v.26 no.6
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• pp.555-559
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• 2004

We propose an efficient digital IF down converter architecture for dual-mode WCDMA/cdma2000 based on the concept of software defined radio. Multi-rate digital filters and fractional frequency conversion techniques are adopted to implement the front end of a dual-mode receiver for WCDMA and cdma2000. A sub-sampled digital IF stage was proposed to support both WCDMA and cdma2000 while lowering the sampling frequency. Use of a CIC filter and ISOP filter combined with proper arrangement of multi-rate filters and common filter blocks resulted in optimized hardware implementation of the front end block in 292k logic gates.

• Journal of electromagnetic engineering and science
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• v.17 no.4
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• pp.233-237
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• 2017

In this paper, a dual-band high frequency (HF) and ultra-high frequency (UHF) radio-frequency identification (RFID) tag antenna is presented that operates in the 13.56 MHz band as well as in the 920 MHz band. A spiral coil along the edges of the antenna substrate is designed to handle the HF band, and a novel meander open complementary split ring resonator (MOCSRR) dipole antenna is utilized to generate the UHF band. The dual-band antenna is supported by a single-feeding port for mono-chip RFID applications. The antenna is fabricated using an FR4 substrate to verify theoretical and simulation designs, and it has compact dimensions of $80mm{\times}40mm{\times}0.8mm$. The proposed antenna also has an omnidirectional characteristic with a gain of approximately 1 dBi.

• Journal of Astronomy and Space Sciences
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• v.27 no.4
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• pp.345-352
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• 2010

Korea multi-purpose satellite-5 (KOMPSAT-5) is a low earth orbit (LEO) satellite scheduled to be launched in 2010. To satisfy the precision orbit determination (POD) requirement for a high resolution synthetic aperture radar image of KOMPSAT-5, KOMPSAT-5 has atmosphere occultation POD (AOPOD) system which consists of a space-borne dual frequency global positioning system (GPS) receiver and a laser retro reflector array. A space-borne dual frequency GPS receiver on a LEO satellite provides position data for the POD and radio occultation data for scientific applications. This paper describes an overview of AOPOD system and operation concepts of the radio occultation mission in KOMPSAT-5. We showed AOPOD system satisfies the requirements of KOMPSAT-5 in performance and stability.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.331-332
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• 2008

A horn antenna having dual-band and dualpolarization operation is proposed. To implement a small-sized structure providing circular polarizations in the Ka- and K-band, the antenna is designed by using the horn radiator on the basis of a conical helix which is exited by two ports for TX and RX in both ends. Through a design optimization process, a compactdual-band and dual-polarized horn antenna having high gain and high isolation performance was realized.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.209-210
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• 2008

We have proposed a bow-tie UWB antenna using a U-shaped stub. The proposed antenna covers the entire ISM frequency (2.45 GHz) and DS-OFDM UWB band ($3.1\;{\sim}\;5\;GHz$). Simulated and measured results are found to be in good agreement with each other. The designed antenna has the figure-of-eight radiation pattern, wide bandwidth, dual-band, and negligible dispersion over the operating frequency band.

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.715-718
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• 2002

TX/RX dual microstrip 1$\times$8 sub-array antennas are designed, fabricated, and measured for a wideband array antennas in communications. They have a Right Handed Circular Polarization (RHCP) for TX from 7.9 to 8.4 GHz and Left Handed Circular Polarization (LHCP) for RX from 7.25 to 7.75 GHz. Two stacked patches are used for a wideband characteristics and cornertruncated square patches are adopted for a circular polarization. To enhance bandwidth characteristics of a circular polarization, 1$\times$2 sequential rotation arrays are applied. From the measured results, 1$\times$8 microstrip sub-array antennas have a good agreement with those of the simulation. Therefore the sub-array antennas are applicable to satellite communication antennas, active phased array antennas, and radiators in other antennas.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2006.07a
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• pp.710-710
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• 2006

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2001.11a
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• pp.25-28
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• 2001

In this paper. to eliminate a cross-polarization interference caused by co-channel dual polarization technique of digital radio relay system(DRRS), a cross-polarization interference canceller(XPIC) is analysed in terms of the analytical modeling, digital design, and its performance. By virtue of a 13-tap adaptive equalizer and XPIC, about 23dB in XPIC improvement can be obtained by computer simulation. To show the operation of designed XPIC, some simulated results are reviewed under 64-QAM DRRS with co -channel dual Polarization.

• Journal of Advanced Navigation Technology
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• v.17 no.1
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• pp.33-38
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• 2013

In this paper, we present the design and measured performances of an dual-band Gysel power divider based on band-stop characteristic. After the Gysel divider is designed by lumped elements at single operating frequency, and then using filter conversion technique the lumped elements were changed a band-stop characteristic with dual-band characteristics. The features of this design method are that ${\lambda}/4$ transmission line by replacing lumped elements suppressed harmonic characteristics and also can reduce the size. To validate of the proposed power divider, the divider has been designed and measured at 880 MHz and 1650 MHz dual frequencies. The measured performances of the Gysel divider agree with prediction results at two frequencies.