• Journal of Advanced Navigation Technology
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• v.13 no.1
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• pp.41-47
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• 2009

In this paper, a band pass filter with a rejection band is proposed for UWB(Ultra Wide Band) communication system. First, low pass filter accessed cut off frequency of 10.2 GHz was designed using structure stepped impedance. And high pass filter accessed cut of frequency of 3.2 GHz was designed using parallel short-stub. There was implemented composite connection of designed low pass filter and high pass filter. The relative dielectric constant, the height, the loss tangent of the PCB substrate were ${\varepsilon}_r$=2.2, h=0.508 mm and loss tangent = 0.0009 respectively. The fabricated band pass filter shows a compact size of 3 cm. The fabricated band pass filter was characterized using 37169A VNA(Vector Network Analyzer). And measured result were obtained 7.5 GHz of bandwidth and -10 dB of return loss and -3 dB of insertion loss from pass band. The result of the research can be used for the UWB communications and MIC/MMIC, RFIC system.

• Journal of Advanced Navigation Technology
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• v.15 no.2
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• pp.197-203
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• 2011

A triple-band antenna which can be used at GSM900, PCS1900 and Bluetooth(or Wi-Fi) frequency band is proposed. The proposed antenna is designed based upon switching between IFA(Inverted F Antenna) that has a resonant length of ${\lambda}/4$ and loop antenna that has a resonant length of ${\lambda}/2$. It can be applied to triple-band only by use of single printed pattern due to the switching characteristic. It is designed by use of the IFA for the application to the GSM900, while it is designed by use of the loop antenna for the application to the PCS1900 and by use of additional pattern of IFA for the application to the Bluetooth(or Wi-Fi) respectively. As a result, it has been observed that the proposed antenna satisfies the required return loss(${\leq}10dB$) and also has efficiency(${\geq}80%$) over the whole band. Moreover the proposed antenna has omni-directional radiation pattern which is suitable to apply to the mobile phone.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.852-855
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• 2012

A DC-DC converter for EEPROM IPs which perfom erasing by the FN (Fowler-Nordheim) tunneling and programming by the band-to-band tunneling is designed in this paper. For the DC-DC converter for EEPROM IPs using a low voltage of $1.5V{\pm}10%$ as the logic voltage, a scheme of using VRD (Read Voltage) instead of VDD is proposed to reduce the pumping stages and pumping capacitances of its charge pump circuit. VRD ($=3.1V{\pm}0.1V$) is a regulated voltage by a voltage regulator using an external voltage of 5V. The designed DC-DC converter outputs VPP (=8V) and VNN (=-8V) in the write mode.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.2
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• pp.105-107
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• 2005

A field study was conducted to investigate and ascertain the effects of boron and molybdenum with recommended N P K S Zn fertilizers (RFD) for sustained sugarcane yield in the sandy acidic soil in Old Himalayan Piedmont Plain of Bangladesh. Results revealed that the treatment $T_7$ having recommended fertilizers of N 120, P 35, K 100, S 25 and Zn 2kg $ha^{-1}$ + B 2kg $ha^{-1}$ + Mo 2 kg $ha^{-1}$ produced significantly higher number of millable cane (126.96\times10^3\;ha^{-1})$ except in $T_9$ with RFD + B 2 kg $ha^{-1}$ + Mo 4kg $ha^{-1}$, and higher cane yield (92.83 Mg $ha^{-1}$) among all except in $T_3$ with RFD + B2 kg $ha^{-1}$, $T_5$ with RFD + Mo 2kg $ha^{-1}$ and $T_9$ where the effects were statistically identical. The increase in cane yield by $T_7$ was $164.6\%$ over control. The treatment $T_7$ having RFD + B 2kg $ha^{-1}$ + Mo 2kg $ha^{-1}$ further gave the highest additional net economic benefit of Taka 16, 500.00 for added Band Mo at 2kg $ha^{-1}$ among all the treatments in the study.

• Journal of Sensor Science and Technology
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• v.16 no.1
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• pp.1-6
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• 2007

A silver indium sulfide ($AgInS_{2}$) epilayer was grown by the hot wall epitaxy method, which has not been reported in the literature. The grown $AgInS_{2}$ epilayer has found to be a chalcopyrite structure and evaluated to be high quality crystal. From the photocurrent measurement in the temperature range from 30 K to 300 K, the two peaks of A and B were only observed, whereas the three peaks of A, B, and C were seen in the PC spectrum of 10 K. These peaks are ascribed to the band-to-band transition. The valence band splitting of $AgInS_{2}$ was investigated by means of the photocurrent measurement. The crystal field splitting, ${\Delta}cr$, and the spin orbit splitting, ${\Delta}so$, have been obtained to be 0.150 eV and 0.009 eV at 10 K, respectively. And, the energy band gap at room temperature has been determined to be 1.868 eV. Also, the temperature dependence of the energy band gap, $E_{g}$(T), was determined.

• Journal of Korean Society on Water Environment
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• v.31 no.3
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• pp.272-285
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• 2015

Accurate assessment of chlorophyll-a (Chl-a) concentrations in inland waters using remote sensing is challenging due to the optical complexity of case 2 waters. and the inherent optical properties (IOPs) of natural waters are the most significant factors affecting light propagation within water columns, and thus play indispensable roles on estimation of Chl-a concentrations. Despite its importance, no IOPs retrieval model was specifically developed for inland water bodies, although significant efforts were made on oceanic inversion models. So we have applied and validated a recently developed Red-NIR three-band model and an IOPs Inversion Model for estimating Chl-a concentration and deriving inland water IOPs in Lake Uiam. Three band and IOPs based Chl-a estimation model accuracy was assessed with samples collected in different seasons. The results indicate that this models can be used to accurately retrieve Chl-a concentration and absorption coefficients. For all datasets the determination coefficients of the 3-band models versus Chl-a concentration ranged 0.65 and 0.88 and IOPs based model versus Chl-a concentration varied from 0.73 to 0.83 respectively. and Comparison between 3-band and IOPs based models showed significant performance with decrease of root mean square error from 18% to 33.6%. The results of this study provides the potential of effective methods for remote monitoring and water quality management in turbid inland water bodies using hyper-spectral remote sensing.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.10
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• pp.1837-1844
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• 2016

This paper proposes an antenna of the fork type structure that operates in the UWB (Ultra Wide Band) frequency band (3.1 ~ 10.6 GHz). The proposed antenna is attached a circular patch in order to obtain the UWB band characteristics to the fork-type patch antenna. The ground plane is implemented in a arc-shape configuration. The effect of various parameters of the modified fork type radiating patch and partial arc ground plane for UWB operation is investigated. The proposed antenna is made of $34.0{\times}50.0{\times}1.0mm^3$ and is fabricated on the permittivity 4.4 FR-4 substrate. The experiment results shown that the proposed antenna obtained the -10 dB impedance bandwidth 8200 MHz (2.7 ~ 10.9 GHz) covering the UWB bands. This result satisfied the characteristics of ultra-wideband and the proposed antenna will be applicable to an ultra wideband system.

• Journal of Advanced Navigation Technology
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• v.23 no.2
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• pp.179-185
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• 2019

In this paper, we have studied narrow-band analog pre-distortion linearization technique using UHF 400 MHz band 20 W power amplifier. The analog pre-distorter used the SC1894 radio frequency power amplifier linearizer(RFPAL) provided by MAXIM Corp and through the look-up table technique confirmed the intermodulation distortion(IMD) performance and the adjusted channel leakage ratio(ACLR) improvement for bandwidth below 1 MHz which does not operate on existing chips. In the 400 MHz (400 ~ 500 MHz) band, IMD performance and the ACLR improvement of up to 17.46 dB based on 1-channel offset and up to 16.6 dB based on 2-channel offset were confirmed. In the system requiring the same linearity, we confirmed power efficiency improvement of 12.41% at output power of over 40 W.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.2
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• pp.95-101
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• 2006

This study was conducted to establish a low-input fertilization technique and increase of fertilization efficiency using the band spotty applicator(1999-2000) during the cultivation of mulching for chinese cabbage(Brassia campestris L.). The obtained results such as nitrogen efficiency, yield and soil improvement after cultivation of chinese cabbage were as follows. The content of $NO_3-N$ in soil increased in band spotty fertilization(BSF) by increasing application rate from the beginning stage to the middle stage. The content of total nitrogen increased but content of organic matter, available phosphate and exchangeable potassium decreased in comparison with the soil before experiment. Growth rate of Chinese cabbage increased in band spotty fertilization plot and uptake amount of nitrogen fertilized for chinese cabbage increased by increasing of the application rate. N use efficiency was higher by 5-21% in band spotty fertilization plot than in conventional fertilization(CF) plot. Yield of chinese cabbage increased by 16% in 70% band spotty fertilization plot and increased by 20% in 100% band spotty fertilization plot. It was found that 70% band spotty fertilization was more effective as fertilization method to reduce both environmental pollution and chemical nitrogen fertilizer in plastic film mulching cultivation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.11A
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• pp.933-940
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• 2011

In this paper, Ka-band transceiver for road watch radar system is designed and fabricated. The transceiver for road watch radar system is composed of waveform generator, frequency generator. IF transceiver and RF up/down converter. The transceiver especially has 3 different waveform mode for target detection range. The transceiver had over 150 MHz bandwidth in Ka-band and 22 dBm output power. The receiver gain and noise figure was 30 dB and 4 dB respectively. The receive dynamic range was 65.28dB and amplitude imbalance and phase imbalance of I/Q channel was 0.3 dB and 1.8 degree respectively. The transceiver meets the required electrical performances through the individual tests.