• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.8
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• pp.764-768
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• 2002

In this paper, a double balanced gilbert cell MMIC mixer was realized in Tachyonics SiGe HBT technology. The fabricated mixer has 17 dB conversion gain, 9.8 dB noise figure, -4.2 dBm output 1 dB compression point, -27 dBc RF to IF isolation, and the good input, output matching characteristics. It draws 10 mA from a 3 V supply. The simulation and the measured results are closer to each other, which confirms accuracy of the model library and reliability of the process.

• Journal of Preventive Medicine and Public Health
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• v.19 no.1 s.19
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• pp.16-30
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• 1986

In order to prepare the fundamental data for the improvement of noisy working environments and the effective hearing conservation program on workers exposed to industrial noise, the authors surveyed the working processes and evaluated the noise levels on 56 manufacturing industries in Pusan area from April to July in 1985. The results were summarized as follows : 1. The noise level was the highest in shipbuilding and repairing(95.6 dBA), and followed by steel rolling(94.0 dBA), manufacture of motor vehicles(93.1 dBA), manufacture of fishing nets(92.9 dBA), manufacture of testiles(92.5 dBA), iron and steel foundries(89.3 dBA), manufacture of metal products(89.1 dBA), preserving and processing of marine foods(87.0 dBA), manufacture of rubber products(85.3 dBA), manufacture of plywood(84.9 dBA) and manufacture of paints(84.5 dBA). 2. Among fifty surveyed working processes, the noise level of twenty-one processes (42%) exceeded the threshold limit value for 8 hours per day. 3. As the allowable exposure times by governmental threshold limit values to industrial noise level(dBA), cocking of shipbuilding and repairing and plating(CGL) of steel rolling were the shortest(30 minutes), and followed by assembling(rivet) of manufacture of motor vehicles(1 hour) weaving of manufacture of textiles and shot, machine, pipe laying of shipbuilding and repairing(2 hours). 4. By the result of octave band analysis on noisy working processes in excess of 90 dBA, the sound level was the highest at 2,000 Hz or 4,000 Hz. 5. It was recognized that the measurement of overall sound pressure level was also effective as octave band analysis in evaluating the industrial noise.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.6
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• pp.141-147
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• 2008

This paper describes the design of frequency down converting Mixer in the receiver to use compound semiconductor and CMOS product process. The basic theory and structure of frequency down converting Mixer is surveyed, and we design mixer circuit with active balun which use the compound semiconductor and CMOS process. This mixer convert a single ended signal to differential signal at input port of RF and LO instead of matching circuit to get dual band balanced mixer structure and characteristic broadband. This designed mixer has a conversion gain $-1{\sim}-6[dB]$ at $2{\sim}6[GHz]$ bandwidths. However, the simulation of the designed mixer with active balun has the result of a 7[dB] conversion gain for -2[dBm] LO input power and -10[dBm] input P1[dB] at 5.8[GHz].

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.3
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• pp.278-285
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• 2013

In this paper, a 100~110 GHz LNA and A coupler using standard 65 n CMOS process is presented. The LNA consists of three common source FET stages. A few layout types are considered to get high gain characteristic of unit common source cell. Also, optimized performance to achieve low noise characteristic and enough gain. Coupler is composed of broadside coupler using multimetal in CMOS fabrication. In the coupler, the metal strip to meet density rule is used, and the coupler is designed with consideration of the metal strip to function properly. Gain of fabricated LNA is 5.64 dB at 100 GHz and 6.39 dB at 110 GHz. Bandwidth is over 10 % and noise figure is 11.66 dB at 100 GHz. Fabricated coupler has shown insertion loss of 2~3 dB at 100~110 GHz band. Magnitude mismatch of coupler is below 1 dB and phase mismatch of coupler is below $5^{\circ}$.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.4
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• pp.131-136
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• 2008

Two Ka-band 3-stage power amplifiers were designed and fabricated using $0.18-{\mu}m$ CMOS technology. For low loss matching networks for the amplifiers, two substrate-shielded transmission line structures, having good modeling accuracy up to 40 GHz were used. The measured insertion loss of substrate-shielded microstrip-line (MSL) was 0.5 dB/mm at 27 GHz. A 3-stage CMOS amplifier using substrate-shielded MSL achieved a 14.7-dB small-signal gain and a 14.5-dBm output power at 27 GHz in a compact chip area of 0.83$mm^2$. The measured insertion loss of substrate-shielded coplanar waveguide (CPW) was 1.0 dB/mm at 27 GHz. A 3-stage amplifier using substrate-shielded CPW achieved a 12-dB small-signal gai and a 12.5-dBm output power at 26.5 GHz. This results shows a potential of CMOS technology for low cost short-range wireless communication components and system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.11
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• pp.1235-1239
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• 2010

In this work, a wideband technique has been proposed that improves the IF bandwidth of mixers and a 24-GHz down-conversion mixer employing the proposed technique has been designed and fabricated based on 0.13-${\mu}m$ RFCMOS technology. The mixer showed the conversion gain of $2.7{\pm}1.5$ dB from DC to 5.25 GHz IF for a fixed LO frequency of 24 GHz. Measured P-1dB and LO-RF isolation was -8.7 dBm and 21 dB, respectively. The mixer draws DC current of 10.6 mA from 1.3 V supply.

• Progress in Superconductivity
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• v.12 no.2
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• pp.88-92
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• 2011

[ $MgB_2$ ]superconducting sheets have been fabricated using powder roll compaction method. Sheet-type $MgB_2$ bulk samples were successfully fabricated using the pre-reacted $MgB_2$ powders. In this work, $MgB_2$ powders were compacted by two rotating rolls and squeezed out as a form of $MgB_2$ sheets of ~1 mm thickness. The rolling speed of 0.3-0.7 rpm and the gap distance of 0.3-0.8 mm between the two rollers were carefully controlled to get a full compaction of the powders into bulk $MgB_2$ sheets. The densities of $MgB_2$ sheets were 1.98-2.05 g/$cm^3$, which is 75.44-77.99 % of the theoretical value of 2.63 g/$cm^3$. And the density comparison was made compared to those of typical $MgB_2$ bulks from uni-axial pressing and $MgB_2$ wires from Powder-In-Tube processing.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.444-449
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• 2001

Because of preferential treatment in PQ judgement, many construction company got the certification of ISO 9000. But the main objective of them was just certification itself. The ISO 9000 certification which was composed of 20 requirements was a standard just for the manufacturing industry, so it was difficult that it was applied to a business of construction industry. In these reasons, they have revised ISO 9000:l994 which was composed or 20 requirements to ISO 9000:2000 which requests to focus on business process. In this research, we'll develop a System for Project Quality Plan that is related with information of site process in an apartment housing project. This system is intended to increase use of project quality plan in construction sites based on the construction process.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.6
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• pp.893-899
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• 2000

A 900 MHz low-noise amplifier(LNA) with a measured noise figure of 4.8 dB and an associated gain of 13.2 dB was fabricated in a 0.65 $\mu$m CMOS. The inductive source architecture of offers the possibility of achieving the best noise performance. At 900 MHz, the fabricated LNA dissipates 39 mW from a single 3 V power supply including the bias circuitry and provides -26dB input return loss, -17 dB output return loss, and an input 1-dB compression level of -12 dBm.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.567-568
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• 2008

In this paper, we proposed the design on LNA for $3{\sim}5\;GHz$ frequency with Using $0.18{\mu}m$CMOS technology. The LNA gain is 12-15 dB, and noise figure is lower than 5 dB and Input/output matching is lower than 10 dB in frequency range from 3 GHz to 5 GHz. The topology, which common source output of cascode is reduced noise figure and improved gain. Input common gate amplifier extend LNA's bandwidth.