• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.11
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• pp.89-94
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• 2011

In this paper, we developed the W-band MMIC low noise amplifier for the millimeter-wave seeker using the tuner system. The MHEMT devices for MMIC LNA exhibited DC characteristics with a drain current density of 692mA/mm, an extrinsic transconductance of 726mS/mm. The current gain cutoff frequency(fT) and maximum oscillation frequency($f_{max}$) were 195GHz and 305GHz, respectively. The fabricated W-band low noise amplifier represented S21 gain of 7.42dB at 94 GHz and noise figure of 2.8dB at 94.2 GHz.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.9
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• pp.25-30
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• 2004

In this Paper, the 0.1 w InGaAs/InAlAs/GaAs Metamorphic HEMT, which is applicable to MIMIC, and a 100 GHz MIMIC amplifier were designed and fabricated. The DC characteristics of MHEMT are 640 mA/mm of drain current density, 653 mS/mm of maximum transconductance. The current gain cut-off frequency(fT) is 173 GHz and the maximum oscillation frequency(fmax) is 271 GHz. A 100 GHz amplifier was designed using 0.1${\mu}{\textrm}{m}$ MHEMT and CPW technology. The measured results from the 100 GHz MIMIC amplifiers show good S21 gain of 10.1 dB and 12.74 dB at 100 GHz and 97.8 GHz, respectively.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.8
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• pp.48-53
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• 2008

In this paper, we developed the MMIC low noise amplifier using 100 nm metamorphic HEMTs technology in combination with coplanar circuit topology for 94 GHz applications. The $100nm\times60{\mu}m$ MHEMT devices for the MMIC LNA exhibited DC characteristics with a drain current density of 655 mA/mm, an extrinsic transconductance of 720 mS/mm. The current gain cutoff frequency $(f_T)$ and maximum oscillation frequency $(f_{max})$ were 195 GHz and 305 GHz, respectively. The realized MMIC LNA represented $S_{21}$ gain of 14.8 dB and noise figure of 4.6 dB at 94 GHz with an over-all chip size of $1.8mm\times1.48mm$.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.12
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• pp.41-46
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• 2008

We report a high gain D-band(110 - 140 GHz) MMIC drive amplifier based on $0.1{\mu}m$ InGaAs/InAlAs/GaAs metamorphic HEMT technology. The amplifier shows an excellent $S_{21}$ gain characteristic greater than 10 dB in a millimeterwave frequency of 110 GHz, Also the amplifier has good reflection characteristics of a $S_{11}$ of -3.5 dB and a $S_{22}$ of -6.5 dB at 110 GHz, respectively The high performances of the MMIC drive amplifier is mainly attributed to the characteristics of the MHEMTs exhibiting a maximum transconductance of 760 mS/mm, a current gain cut-off frequency of 195 GHz and a maximum oscillation frequency of 391 GHz.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.7 s.361
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• pp.31-36
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• 2007

A saw-tooth waveform generator whose frequency can be controlled with a do bias current is proposed. The generator utilizes operational transconductance amplifiers (OTA's) as switching element. It features simple and wide sweep capability The circuit built with commercially avaliable components exhibits good linearity of current-to-frequency transfer characteristics and relatively low temperature sensitivity.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.8
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• pp.105-111
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• 2004

In this paper, millimeter-wave high gain and broadband MHEMT cascode amplifiers were designed and fabricated. The 0.1 ${\mu}{\textrm}{m}$ InGaAs/InAlAs/GaAs Metamorphic HEMT was fabricated for cascode amplifiers. The DC characteristics of MHEMT are 640 mA/mm of drain current density, 653 mS/mm of maximum transconductance. The current gain cut-off frequency(f$_{T}$) is 173 GHz and the maximum oscillation frequency(f$_{max}$) is 271 GHz. By using the CPW transmission line, the cascode amplifier was designed the matched circuit for getting the broadband characteristics. The designed amplifier was fabricated by the MHEMT MIMIC process that was developed through this research. As the results of measurement, the 1 stage amplifier obtained 3 dB bandwidth of 37 GHz between 31.3 to 68.3 GHz. Also, this amplifier represents the S21 gain with the average 9.7 dB gain in bandwidth and the maximum gain of 11.3 dB at 40 GHz. The 2 stage amplifier has the broadband characteristics with 3 dB bandwidth of 29.5 GHz in the frequency range from 32.5 to 62.0 GHz. The 2 stage cascode amplifier represents the high gain characteristics with the average gain of 20.4 dB in bandwidth and the maximum gain of 22.3 dB at 36.5 GHz.z.z.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.12
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• pp.7-12
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• 2004

In this paper, CPW wideband distributed amplifier was designed and fabricated using 0.1 $\mum$ InGaAs/InAlAs/GaAs Metamorphic HEMT(High Electron Mobility Transistor). The DC characteristics of MHEMT are 442 mA/mm of drain current density, 409 mS/mm of maximum transconductance. The current gain cut-off frequency(fT) is 140 GHz and the maximum oscillation frequency(fmax) is 447 GHz. The distributed amplifier was designed using 0.1 $\mum$ MHEMT and CPW technology. We designed the structure of CPW curve, tee and cross to analyze the discontinuity characteristics of the CPW line. The MIMIC circuit patterns were optimized electromagnetic field through momentum. The designed distributed amplifier was fabricated using our MIMIC standard process. The measured results show S21 gain of above 6 dB from DC to 45 GHz. Input reflection coefficient S11 of -10 dB, and output reflection coefficient S22 of -7 dB at 45 GHz, respectively. The chip size of the fabricated CPW distributed amplifier is 2.0 mm$\times$l.2 mm.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.4
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• pp.1-6
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• 2008

In this paper, millimeter-wave broadband MHEMT (Metamorphic High Electron Mobility Transistor) cascode amplifiers were designed and fabricated. The $0.1{\mu}m$ InGaAs/InAlAs/GaAs MHEMT was fabricated for cascode amplifiers. The DC characteristics of MHEMT are 670 mA/mm of drain current density, 588 mS/mm of maximum transconductance. The current gain cut-off frequency($f_T$) is 139 GHz and the maximum oscillation frequency($f_{max}$) is 266 GHz. To prevent oscillation of the designed cascode amplifiers, a parallel resistor and capacitor were connected to the drain of common gate device. By using the CPW (Coplanar Waveguide) transmission line, the cascode amplifier was designed and matched for the broadband characteristics. The designed amplifier was fabricated by the MHEMT MMIC process that was developed through this research. As the results of measurement, the amplifier was obtained 3 dB bandwidth of 50.37 GHz between 20.76 to 71.13 GHz. Also, this amplifier represents the S21 gain with the average 7.07 dB gain in bandwidth and the maximum gain of 10.3 dB at 30 GHz.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.11
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• pp.21-27
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• 2004

In this paper, millimeter-wave monolithic integrated circuit(MIMIC) low noise amplifier(LNA) for V-band, which is applicable to 60 GHz wireless local area network(WLAN), was fabricated using the high performance 0.1 ${\mu}{\textrm}{m}$ $\Gamma$-gate pseudomorphic high electron mobility transistor(PHEMT). The DC characteristics of PHEMT are drain saturation current density(Idss) of 450 mA/mm and maximum transconductance(gm, max) of 363.6 mS/mm. The RF characteristics were obtained the current gain cut-off frequency(fT) of 113 GHz and the maximum oscillation frequency(fmax) of 180 GHz. V-band MIMIC LNA was designed using active and passive device library, which is composed of 0.1 ${\mu}{\textrm}{m}$ $\Gamma$-gate PHEMT and coplanar waveguide(CPW) technology. The designed V-band MIMIC LNA was fabricated using integrated unit processes of active and passive device. The measured results of V-band MIMIC LNA are shown S21 gain of 21.3 dB, S11 of -10.6 dB at 60 GHz and S22 of -29.7 dB at 62.5 GHz. The measured result of V-band MIMIC LNA was shown noise figure (NF) of 4.23 dB at 60 GHz.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.1
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• pp.38-46
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• 1999

o.25${\mu}m$ T-shaped gate P-HEMT is fabricated and used for design of X0band three stage monolithic microwave integrated circuit(MMIC) low noise amplifier(LNA). The fabricated P-HEMT exhibits an extrinsis transconductance of 400mS/mm and a drain current of 400mA/mm. The RF and noise characteristics show that the current gain cut off frequency is 65GHz and minimum noise figure(NFmin) of 0.7dB with an associated gain of 14.8dB at 9GHz. In the design of the three stage LNA, we have used the inductive series feedback circuit topology with the short stub. The effects of series feedback to the noise figure, the gain, and the stability have been investigated to find the optimal short stub length. The designed three staage LNA showed a gain of above 33dB, a noise figure of under 1.2dB, and ainput/output return loss of under 15dB and 14dB, respectively. The results show that the fabricated P-HEMT is very suitable for a X-band LNA with high gain.