• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.227-228
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• 2006

In this paper, we introduce the design and fabrication of 60 GHz low noise amplifier MMIC for IEEE802.15.3c WPAN system. The 60 GHz LNA was designed using ETRI's $0.12{\mu}m$ PHEMT process. The PHEMT shows a peak transconductance ($G_{m,peak}$) of 500 mS/mm, a threshold voltage of -1.2 V, and a drain saturation current of 49 mA for 2 fingers and $100{\mu}m$ total gate width (2f100) at $V_{ds}$=2 V. The RF characteristics of the PHEMT show a cutoff frequency, $f_T$, of 97 GHz, and a maximum oscillation frequency, $f_{max}$, of 166 GHz. The performances of the fabricated 60 GHz LNA MMIC are operating frequency of $60.5{\sim}62.0\;GHz$, small signal gain ($S_{21}$) of $17.4{\sim}18.1\;dB$, gain flatness of 0.7 dB, an input reflection coefficient ($S_{11}$) of $-14{\sim}-3\;dB$, output reflection coefficient ($S_{22}$) of $-11{\sim}-5\;dB$ and noise figure (NF) of 4.5 dB at 60.75 GHz. The chip size of the amplifier MMIC was $3.8{\times}1.4\;mm^2$.

• JSTS:Journal of Semiconductor Technology and Science
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• v.3 no.1
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• pp.27-32
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• 2003

Highly reproducible side-wall process for the fabrication of the fine gate length as small as 40nm was developed. This process was utilized to fabricate 40nm InGaAs HEMTs with the 65% strained channel. With the usage of the dual $SiO_2$ and $SiN_x$ dielectric layers and the proper selection of the etching gas, the final gate length (Lg) was insensitive to the process conditions such as the dielectric over-etching time. From the microwave measurement up to 40GHz, extrapolated fT and fmax as high as 371 and 345 GHz were obtained, respectively. We believe that the developed side-wall process would be directly applicable to finer gate fabrication, if the initial line length is lessened below the l00nm range.

• 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 $1.8mm\times1.48mm$.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.857-860
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• 2005

We reported 94 GHz, low conversion loss, and high isolation single balanced active-gate mixer based on 70 nm gate length InGaAs/InAlAs metamorphic high electron mobility transistors (MHEMTs). This mixer showed that the conversion loss and isolation characteristics were 2.5 ${\sim}$ 2.8 dB and under -30 dB, respectively, in the range of 93.65 ${\sim}$ 94.25 GHz. The low conversion loss of the mixer is mainly attributed to the high-performance of the MHEMTs exhibiting a maximum drain current density of 607 mA/mm, a extrinsic transconductance of 1015 mS/mm, a current gain cutoff frequency ($f_t$) of 330 GHz, and a maximum oscillation frequency ($f_{max}$) of 425 GHz. High isolation characteristics are due to hybrid ring coupler which adopted dielectric-supported air-gapped microstrip line (DAML) structure using surface micromachined technology. To our knowledge, these results are the best performance demonstrated from 94 GHz single balanced mixer utilizing GaAs-based HEMTs in terms of conversion loss as well as isolation characteristics.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.2
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• pp.128-135
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• 2013

This letter presents the MISHFET with si-doped AlGaN/GaN heterostructure for power amplifier. The device grown on 6H-SiC(0001) substrate with a gate length of 180 nm has been fabricated. The fabricated device exhibited maximum drain current density of 837 mA/mm and peak transconductance of 177 mS/mm. A unity current gain cutoff frequency was 45.6 GHz and maximum frequency of oscillation was 46.5 GHz. The reported output power density was 1.54 W/mm and A PAE(Power Added Efficiency) was 40.24 % at 9.3 GHz.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.4 s.346
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• pp.8-15
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• 2006

In this paper, the 94 GHz, low conversion loss, and high isolation single balanced mixer is designed and fabricated using GaAs-based metamorphic high electron mobility transistors (MHEMTs) with 70 nm gate length and the hybrid ring coupler with the micromachined transmission lines, dielectric-supported air-gapped microstrip lines (DAMLs). The 70 nm MHEMT devices exhibit DC characteristics with a drain current density of 607 mA/mm an extrinsic transconductance of 1015 mS/mm. The current gain cutoff frequency ($f_T$) and maximum oscillation frequency ($f_{max}$) are 320 GHz and 430 GHz, respectively. The fabricated hybrid ring coupler shows wideband characteristics of the coupling loss of $3.57{\pm}0.22dB$ and the transmission loss of $3.80{\pm}0.08dB$ in the measured frequency range of 85 GHz to 105 GHz. This mixer shows that the conversion loss and isolation characteristics are $2.5dB{\sim}>2.8dB$ and under -30 dB, respectively, in the range of $93.65GHz{\sim}94.25GHz$. At the center frequency of 94 GHz, this mixer shows the minimum conversion loss of 2.5 dB at a LO power of 6 dBm To our knowledge, these results are the best performances demonstrated from 94 GHz single balanced mixer utilizing GaAs-based HEMTs in terms of conversion loss as well as isolation characteristics.