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Dong Sik Ko,
Mun-Kyo Lee,
Dan An, Bok-Hyung Lee,
Byeong-Ok Lim,
Sang Jin Lee,
Sung-Woon Moon,
Byoung-Chul Jun,
Seok Ho Bang,
Jung-Dong Park,
Wan Joo Kim,
Sam-Dong Kim,
Jin-Koo Rhee
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ABSTRACT: In this paper, we present a high performance 94 GHz MMIC diode mixer using a 100-nm metamorphic high electron mobility transistor (MHEMT) diode and coplanar waveguide (CPW) 3-dB tandem coupler. A novel single-balanced structure of MHEMT diode mixer was proposed in this work, and 3-dB tandem coupler with the air-bridge structure was used for broadband LO-RF isolation. The fabricated mixer has LO-RF isolation, greater than 19 dB, in 15 GHz bandwidth of 82-97 GHz. The good conversion loss of 14.8 dB was measured at 94 GHz.
Microwave Conference, 2007. APMC 2007. Asia-Pacific; 01/2008
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Mun-Kyo Lee,
Jung-Dong Park,
Dan An, Bok-Hyung Lee,
Sung-Chan Kim,
Byeong-Ok Lim,
Sang-Jin Lee,
Yeon-Sik Chae,
Wan-Joo Kim,
Yong-Hoh Kim,
Jin-Koo Rhee
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ABSTRACT: In this paper, we report our recent research works on the W-band waveguide-to-CPW transitions for various MIMIC applications. For this, the transitions operating in a frequency range of 85 ~ 100 GHz are designed, fabricated and characterized. The designed waveguide-to-CPW transition is optimized to achieve low loss by using an EM field solver of HFSS. From the measurement, an insertion of -2.2 dB and a return loss of -23.86 dB, respectively, were obtained at 94 GHz. The average insertion loss of waveguide-to-CPW back-to-back transition is -2.5 dB in a frequency range of 85 ~ 100 GHz.
Communications and Electronics, 2006. ICCE '06. First International Conference on; 11/2006
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ABSTRACT: We report a low conversion loss and high local oscillator (LO)-to-RF isolation 94-GHz monolithic-microwave integrated-circuit (MMIC) active down converter using 0.1-mum InGaAs/InAlAs/GaAs metamorphic high electron-mobility transistor (MHEMT). The fabricated MMIC active down converter employs a one-stage MHEMT amplifier in the RF port of the active down converter, thereby amplifying the RF signal and improving the LO-to-RF isolation by using an inherent S<sub>12</sub> isolation characteristic. The fabricated MMIC active down converter shows an excellent conversion loss of 6.7 dB at an LO power of 10 dBm and high LO-to-RF isolations of 21 plusmn 0.5 dB in a frequency range from 93.7 to 94.3 GHz. High dc and RF performances of the MHEMT used for the active down converter are due to the optimized epitaxial and device structure, and a maximum transconductance of 760 mS/mm, a current gain cutoff frequency of 195 GHz, and a maximum oscillation frequency of 391 GHz were measured. A active down-converter module is assembled by mounting the active down-converter chip on a jig with low-loss transition structure between the coplanar waveguide and waveguide. The fabricated active down-converter module shows a good conversion loss of 10.9 dB and a very high LO-to-RF isolation of 27.5 dB at 94.03 GHz
IEEE Transactions on Microwave Theory and Techniques 07/2006; · 1.85 Impact Factor
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Mun-Kyo Lee,
Jung-Dong Park,
Dan An, Bok-Hyung Lee,
Sang-Jin Lee,
Tae-Jong Baek,
Jung-Hun Oh,
Sung-Woon Moon,
Hyuk-Ja Kwon,
Wan-Joo Kim,
Yong-Hoh Kim,
Hyung-Moo Park,
Jin-Koo Rhee
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ABSTRACT: For low LO power and broadband characteristics of the mixer, an antipodal fin-line to microstrip transition for operation in the 94 GHz frequency has been designed and characterized. Back to back transitions fabricated on soft substrates have been measured and simulated to verify their behavior. A single balanced fin-line mixer was designed and fabricated. In the mixer, a wideband fin-line to coplanar waveguide 180° balun and low pass filter were used. Conversion loss is less than 10 dB at LO power of 6 dBm.
Microwave Conference Proceedings, 2005. APMC 2005. Asia-Pacific Conference Proceedings; 01/2006
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ABSTRACT: We report high switching performance of 0.1-μm metamorphic high-electron mobility transistors (HEMTs) for microwave/millimeter-wave monolithic integrated circuit (MMIC) resistive mixer applications. Very low source/drain resistances and gate capacitances, which are 56 and 31% lower than those of conventional pseudomorphic HEMTs, are due to the optimized epitaxial and device structure. Based on these high-performance metamorphic HEMTs, a 94-GHz MMIC resistive mixer was designed and fabricated, and a very low conversion loss of 8.2 dB at a local oscillator power of 7 dBm was obtained. This is the best performing W-band resistive field-effect transistor mixer in terms of conversion loss utilizing GaAs-based HEMTs reported to date.
IEEE Electron Device Letters 11/2005; · 2.85 Impact Factor
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ABSTRACT: We report broadband high-gain W-band monolithic microwave integrated circuit amplifiers based on 0.1-μm InGaAs-InAlAs-GaAs metamorphic high electron mobility transistor (MHEMT) technology. The amplifiers show excellent S<sub>21</sub> gains greater than 10 dB in a very broad W-band frequency range of 75-100 GHz, thereby exhibiting a S<sub>21</sub> gain of 10.1 dB, a S<sub>11</sub> of -5.1 dB and a S<sub>22</sub> of -5.2 dB at 100 GHz, respectively. The high gain of the amplifier is mainly attributed to the performance of the MHEMTs exhibiting a maximum transconductance of 691 mS/mm, a current gain cutoff frequency of 189 GHz, and a maximum oscillation frequency of 334 GHz.
IEEE Electron Device Letters 01/2005; · 2.85 Impact Factor
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Microelectronics Journal. 01/2004; 35:973-983.
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ABSTRACT: A high conversion gain receiver chip set for Q-band millimeter-wave wireless communication systems is designed and fabricated by using 0.1 μm GaAs-based pseudomorphic high electron mobility transistors (PHEMTs) and the coplanar waveguide (CPW) library. The fabricated receiver chip set consists of a subharmonic mixer circuit and a low noise amplifier. From the device characterization, the subharmonic mixer shows a maximum conversion gain of ∼4.8 dB at an RF frequency of 40 GHz for a local oscillation (LO) power of 10 dBm at 17.5 GHz. The subharmonic mixer also exhibits a high degree of isolation characteristic of -35.8 dB for LO-to-IF and -40.5 dB for LO-to-RF, respectively, at a LO frequency of 17.5 GHz. The low noise amplifier shows a S<sub>21</sub> gain of ∼25.6 dB at a RF frequency of 40 GHz. Due to the high performances of the circuits, the fabricated receiver chip set produces a high conversion gain of 30.4 dB for the Q-band application purpose.
TENCON 2003. Conference on Convergent Technologies for Asia-Pacific Region; 11/2003
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ABSTRACT: In this paper, we have designed and fabricated high conversion gain Q-band active sub-harmonic mixers for a receiver of millimeter wave wireless communication systems. The fabricated active sub-harmonic mixer uses 2nd harmonic signals of a low local oscillator (LO) frequency. The fabricated mixer was successfully integrated by using 0.1 µm GaAs pseudomorphic high electron mobility transistors (PHEMTs) and coplanar waveguide (CPW) structures. From the measurement, it shows that maximum conversion gain of 4.8 dB has obtained at a RF frequency of 40 GHz for 10 dBm LO power of 17.5 GHz. Conversion gain from the fabricated sub-harmonic mixer is one of the best reported thus far. And a phase noise of the 2nd harmonic was obtained -90.23 dBc/Hz at 100 kHz offset. The active sub-harmonic mixer also ensure a high degree of isolations, which are -35.8 dB from LO-to-IF and -40.5 dB from LO-to-RF, respectively, at a LO frequency of 17.5 GHz.
01/2003; 3.
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ABSTRACT: We have designed and fabricated a low LO power V-band CPW mixer using GaAs PHEMT technology for the application of millimeter-wave wireless communication systems. The mixer was designed using a unique gate mixing architecture to achieve simultaneously a low LO input power, a high conversion gain, and good LO-RF isolation characteristics. The V-band mixer was fabricated using the MIMIC process including 0.1-? GaAs PHEMTs and CPW transmission lines. The V-band mixer exhibited a high conversion gain of 2 dB at a low LO power of 0 dBm. The low LO power and the high conversion gain achieved in this work is among the best ever reported for a V-band mixer.
Microwave Conference, 2002. 32nd European; 10/2002
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ABSTRACT: We investigated the effects of recovery schemes on the characteristics of GaN Schottky diodes damaged by inductively coupled
plasma etching. The recovery schemes included
plasma exposure,
plasma plus annealing at 600°C in
and annealing at 700°C in
Ga-deficient GaN surface layers were observed after etching the GaN, and the Ga/N stoichiometry at the surface was most strongly
affected by the
flow rate among the process variables. The samples annealed at 700°C showed a clear improvement in diode characteristics
and a complete restoration of the Ga/N ratio from ca. 0.87 to ca. 1.0 at the surface layers, as measured by Auger electron spectroscopy. For all other damage-recovery schemes, the samples
showed no significant enhancement in diode characteristics and incomplete restoration of Ga/N stoichiometry at the surface
layers. © 2001 The Electrochemical Society. All rights reserved.
Journal of The Electrochemical Society. 09/2001; 148(10):G592-G596.
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ABSTRACT: To perform a comparative study, we experimented on two differential epitaxial structures, the conventional metamorphic high-electron-mobility-transistor (MHEMT) using the InAlAs/InGaAs/InAlAs structure and the InP-composite-channel MHEMT adopting the InAlAs/InGaAs/InP structure. Compared with the conventional MHEMT, the InP-composite-channel MHEMT shows improved breakdown performance; more than approximately 3.8 V. This increased breakdown voltage can be explained by the lower impact ionization coefficient of the InP-composite-channel MHEMT than that of the conventional MHEMT. The InP-composite-channel MHEMT also shows improved Radio Frequency characteristics of S 21 gain of approximately 4.35 dB at 50 GHz, and a cutoff frequency ( f T ) and a maximum frequency of oscillation ( f max ) of approximately 124 GHz and 240 GHz, respectively, were obtained. These are due to decreases in g o and g m
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ABSTRACT: We examine the effects of device scaling in both vertical and lateral dimensions for the metamorphic high electron mobility transistors (MHEMTs) on the DC and millimeter-wave electrical performances by using a hydrodynamic transport model. The well-calibrated hydrodynamic simulation for the sub-0.1-μm offset Γ-gate In0.53Ga0.47As/In0.52Al0.48As MHEMTs shows a reasonable agreement with the electrical characteristics measured from the fabricated 0.1 μm devices. We have calibrated all the parameters using the measurement data with various physical considerations to take into account the sophisticated carrier transport physics in sub-0.1-μm devices. Being simulated with these calibrated parameters, the optimum device performance is obtained at a source-drain spacing of 2 μm, a gate length of 0.05 μm, a barrier thickness of 10 nm and a channel thickness of 12 nm.
Microelectronics Journal.
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ABSTRACT: In this work,,we present the characteristics of the 0.1 ໃ gate length InGaAs/InAlAs/GaAs metamorphic high electron mobility transistors (MHEMTs). The MHEMTs with ī-shaped off-set gates (70 ໃ width and 2 fingers)were fabricated using the double heterostructure epitaxial structure and characterized through the DC,Noise and RF measurements.Measured channel current density and transconductance (gm )were 442 mA/mm and 409 mS/mm,respectively.Noise characteristics were measured in the frequency range from 50 GHz to 61 GHz,and show 1.8 dB at 50GHz.From RF measurements,154 and 433 GHz were obtained for the cut- off frequency (fT )and maximum frequency of oscillation (fmax ),respectively.A superior fmax of 433 GHz achieved in the work is one of the first reports among the fabricated 0.1 ໃ gate length MHEMTs.
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ABSTRACT: In this paper, we have designed and fabricated high conversion gain Q-band active sub-harmonic mixers for a receiver of millimeter-wave wireless communication systems. The fabricated active sub-harmonic mixer used second harmonic signals of a low local oscillator (LO) frequency. The fabricated mixer were successfully integrated by using a 0.1 μm GaAs pseudomorphic HEMT’s and a coplanar waveguide structure. We showed that the highest conversion gain of 4.8 dB has obtained at a LO frequency of 17.5 GHz and a RF frequency of 40 GHz. Conversion gain from the fabricated sub-harmonic mixer is one of the best reported thus far. The active sub-harmonic mixer also ensure a high degree of isolations, which are −35.8 dB from LO-to-IF and −40.5 dB from LO-to-RF, respectively, at a LO frequency of 17.5 GHz.
Current Applied Physics.
