• Proceedings of the IEEK Conference
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• 2000.06b
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• pp.84-87
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• 2000

In this paper, a high gain-broad bandwidth MMIC distributed amplifier was designed using cascaded single section distributed amplifier configuration. The PHEMT for this studies was fabricated at our lab The PHEMT has a 0.2 $\mu\textrm{m}$ gate length. a 80 $\mu\textrm{m}$ unit gate width and 4 gate fingers. A designed MMIC amplifier have higher S$\sub$21/ gain than the common distributed amplifier using the same number of active devices. From the simulated result, we obtained that the S$\sub$21/ gain of DC ∼ 20 GHz bandwidth was 15.6 dB and flatness was ${\pm}$0.9 dB, and input and output reflection coefficient were lower than -8 dB. The simulated gain shows an improvement 7.3 dB compared with those of conventional distributed amplifier. And the chip size is 2.0 ${\times}$ 1.2 $\textrm{mm}^2$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.9
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• pp.743-749
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• 2002

A 1.5V 70㏈ 100MHz CMOS class-AB complementary operational amplifier is presented. For obtaining the high gain and the high unity gain frequency, the input stage of the amplifier is designed with rail-to-rail complementary differential pairs which are symmetrically parallel-connected with the NMOS and the PMOS differential input pairs, and the output stage is designed to the rail-to-rail class-AB output stage including the elementary shunt stage technique. With this design technique for output stage, the load dependence of the overall open loop gain is improved and the push-pull class-AB current control can be implemented in a simple way. The designed operational amplifier operates perfectly on the complementary mode with 180$^{\circ}$ phase conversion for 1.5V supply voltage, and shows the push-pull class-AB operation. In addition, the amplifier shows the DC open loop gain of 70.4 ㏈ and the unity gain frequency of 102 MHz for $C_{L=10㎊∥}$ $R_{L=1㏁}$ Parallel loads. When the resistive load $R_{L}$ is varied from 1 ㏁ to 1 ㏀, the DC open loop gain of the amplifier decreases by only 2.2 ㏈.a$, the DC open loop gain of the amplifier decreases by only 2.2 dB.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.7
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• pp.1249-1255
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• 2008

1530nm band has been studied as pump wavelength for long-wavelength-band erbium-doped fiber amplifier (L-band EDFA). The pump source is built using a tunable light source and cascaded conventional-band (C-band) EDFA. The L-band EDFA uses a forward pumping scheme. Within the 1530nm band, 1545nm pump demonstrates 0.45dB/mW gain coefficient, which is twice better than that of conventional 1480nm pumped EDFA. The noise figure of 1530nm pump is at worst 6.36dB, which is 0.75dB higher than that of 1480nm pumped EDFA. Such high gain coefficient indicates that the L-band EDFA consumes low power.

• Journal of the Korean Society of Food Science and Nutrition
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• v.19 no.2
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• pp.121-126
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• 1990

Internal mass transfer during osmotic concentration of apples in sugar solutions was exami-ned as a function of concentration temperature and immersion time of those solutions using moisture loss sugar gain molality and rate parameter. Influence of osmotic concentration processes on browning reaction was also evaluated compared to control In creasin the concen-tration and temperature of sugar solutions increased moistrue loss sugar gain molality and rate parameter. Water loss was rapid early in the process and then levelled off, The same phenomena were occurred on sugar gain only in higher concentration(60$^{\circ}$ brix). IN lower concentration (30$^{\circ}$brix) sugar gain was gradually increased during whole process. Moisture loss during osmotic concentration using a sugar solution(60$^{\circ}$ brix 6$0^{\circ}C$) with 180min immer-sion time was 45.79% Effect of osmotic concentration befor air dried to 4% M.C(wet basis) on browning reaction was significant. Minimum browning reaction during air drying was carried out using a pretreatment such as osmotic concentration in sugar solution(60$^{\circ}$brix 45$^{\circ}C$) with 150min immersion time(O.D=0.01) compared to control(O.D=0.17)

• Journal of the Korean Institute of Telematics and Electronics
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• v.9 no.5
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• pp.27-33
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• 1972

This paper describes the computer-aided design, fabrication and performance of high Q and high gain active filters suitable for microminiaturization in the frequency range of 10-800MHz, based on the negative resistance operation of a transistor. 48 as high as 1000 and a transducer gain as high as 35dB can readily be obtained with a single-transistor amplifier and with an inductance as small as a few nH at higher frequencies and 150 nH at lower frequencies in tile above frequency range. The gain of the proposed active filter can be stoabilized within $\pm$ 1.5 dB over the temperature range -1$0^{\circ}C$ to +5$0^{\circ}C$ and the temperature dependence of the center frequency is tapicalla 50ppm/$^{\circ}C$. An experimental FM receiver utilizing these fitters and operating at a carrier frequency of 92 MH3 was built. The whole circuit was fabricated on eight alumina substrates of by the thick-film hybrid IC technique and the coils are constructed, for miniaturization, in a spiral form of 3 or 4 turns of enamel copper wire with an overall diameter of about 5mm. The test results are also reported in this paper.

• ETRI Journal
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• v.24 no.2
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• pp.81-96
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• 2002

This paper describes our design of a hybrid amplifier composed of a distributed Raman amplifier and erbium-doped fiber amplifiers for C- and L-bands. We characterize the distributed Raman amplifier by numerical simulation based on the experimentally measured Raman gain coefficient of an ordinary single mode fiber transmission line. In single channel amplification, the crosstalk caused by double Rayleigh scattering was independent of signal input power and simply given as a function of the Raman gain. The double Rayleigh scattering induced power penalty was less than 0.1 dB after 1000 km if the on-off Raman gain was below 21 dB. For multiple channel amplification, using commercially available pump laser diodes and fiber components, we determined and optimized the conditions of three-wavelength Raman pumping for an amplification bandwidth of 32 nm for C-band and 34 nm for L-band. After analyzing the conventional erbium-doped fiber amplifier analysis in C-band, we estimated the performance of the hybrid amplifier for long haul optical transmission. Compared with erbium-doped fiber amplifiers, the optical signal-to-noise ratio was calculated to be higher by more than 3 dB in the optical link using the designed hybrid amplifier.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.5
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• pp.903-907
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• 1998

Mass transfer characteristics during osmotic dehydration of mushrooms(Agaricus bisporus) in sugar solution were studied as a function of sugar concentration, immersion time and temperature, and the effect of osmotic dehydration on browning inhibition of air-dried mushrooms was also evaluated. Increasing the sugar concentration, immersion time and temperature increased moisture loss, sugar gain, molality and rate parameter. The changes of sugar gain and rate parameter were more significantly affected by concentration than by temperature of sugar solutions, while 1$0^{\circ}C$ increase in temperature or 10 Brix increase in concentration had the same effect on water loss. Water loss, sugar gain, molality were rapid in the first period of osmotic dehydration especially in the case of higher concentration and temperature of sugar solutions. Effects of osmotic dehydration in sugar solution(60 Brix, 8$0^{\circ}C$) with 18 min of immersion time(O.D.=0.099) rior to air dehydration on browning inhibition of dried mushrooms were more significant than blanching in water(8$0^{\circ}C$) with the same immersion time(O.D.=0.330) and the control (O.D.=0.559).

• KIEE International Transactions on Electrophysics and Applications
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• v.11C no.4
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• pp.99-106
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• 2001

An overview of Silicon Carbide (SiC) Static Induction Transistor (SIT) development is presented. Basic conduction mechanisms are introduced and discussed, including ohmic, exponential, and space charge limited conduction (SCLC) mechanisms. Additionally, the impact of velocity saturation and temperature effects on SCLC are reviewed. The small-signal model, breakdown voltage, power density, and different gate structures are also discussed, before a final review of published SiC SIT results. Published S-band (3-4 GHz) results include 9.5 dB of gain and output power of 120 W, and L-band (1.3 GHz) results include 400 W output power, 7.7 dB of gain, and power density of 16.7 W/cm.

• ETRI Journal
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• v.42 no.5
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• pp.781-789
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• 2020

In this study, an E-band low-noise amplifier (LNA) monolithic microwave integrated circuit (MMIC) has been designed using silicon-germanium 130-nm bipolar complementary metal-oxide-semiconductor technology to suppress unwanted signal gain outside operating frequencies and improve the signal gain and noise figures at operating frequencies. The proposed impedance-controllable filter has series (R_s) and parallel (R_p) resistors instead of a conventional inductor-capacitor (L-C) filter without any resistor in an interstage matching circuit. Using the impedance-controllable filter instead of the conventional L-C filter, the unwanted high signal gains of the designed E-band LNA at frequencies of 54 GHz to 57 GHz are suppressed by 8 dB to 12 dB from 24 dB to 26 dB to 12 dB to 18 dB. The small-signal gain S₂₁ at the operating frequencies of 70 GHz to 95 GHz are only decreased by 1.4 dB to 2.4 dB from 21.6 dB to 25.4 dB to 19.2 dB to 24.0 dB. The fabricated E-band LNA MMIC with the proposed filter has a measured S₂₁ of 16 dB to 21 dB, input matching (S₁₁) of -14 dB to -5 dB, and output matching (S₂₂) of -19 dB to -4 dB at E-band operating frequencies of 70 GHz to 95 GHz.

• Journal of Navigation and Port Research
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• v.31 no.10
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• pp.833-837
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• 2007

In this study, we have fabricated a gain flattened erbium-doped optical fiber amplifier. Gain flattening filters were realized by the strain-induced long period fiber gratings, which are made of periodically arrayed metal wires. Using the filter of $550{\mu}m$ period, spontaneous emission amplified at C-band wavelength by a 980nm pumping laser was flattened within 1dB of gain ripple. The performance of the simultaneous multi channel amplification was measured using a fabry-perot laser diode. Amplification ratio was above 20dB. This amplifier can be applied to the long distance transmission system based on a wavelength division multiplexing for boosting an attenuated signal.