• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.491-492
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• 2006

The MMIC (Microwave Monolithic Integrated Circuit) self oscillating double conversion mixer was designed and fabricated for the V-band transmitter applications. The MMIC self oscillating double conversion mixer which dose not need external local oscillator was designed using GaAs PHEMT technology. The first self oscillating mixer use PHEMT technology. The first self oscillating mixer use PHEMT for $f_{LO}$ signal generation and $f_{IF}$ signal is applied at gate port and $f_{RF1}$ signal is generated at a drain port of first stage. The second gate mixer use PHEMT for $f_{LO}$ signal and $f_{RF1}$ signal is applied at gate port and $f_{RF2}$ signal is output at a drain port of second stage.

• Journal of information and communication convergence engineering
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• v.2 no.2
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• pp.93-96
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• 2004

The a-Si:H TFT using ferroelectric of $SrTiO_3$ as a gate insulator is fabricated on glass. Dielectric characteristics of ferroelectric are superior to $SiO_2$ and $Si_{3}N_{4}$. Ferroelectric increases on-current, decreases threshold voltage of TFT and also improves breakdown characteristics. The a-SiN:H has optical band gap of 2.61 eV, retractive index of 1.8∼2.0 and resistivity of $10^{13}$~$10^{15}$ $\Omega$cm, respectively. Insulating characteristics of ferroelectrics are excellent because dielectric constant of ferroelectric is about 60∼100 and breakdown strength is over 1MV/cm. TFT using ferroelectric has channel length of 8∼20 $\mu\textrm{m}$ and channel width of 80∼200 $\mu\textrm{m}$. And it shows that drain current is 3.4$\mu\textrm{A}$ at 20 gate voltage, $I_{on}$/$I_{off}$ is a ratio of $10^5$~$10^8$ and $V_{th}$ is 4∼5 volts, respectively. In the case of TFT without ferroelectric, it indicates that the drain current is 1.5 $\mu\textrm{A}$ at 20 gate voltage and $V_{th}$ is 5∼6 volts. With the improvement of the ferroelectric thin film properties, the performance of TFT using this ferroelectric has advanced as a gate insulator fabrication technology is realized.

• ETRI Journal
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• v.42 no.4
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• pp.549-561
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• 2020

We developed a 0.1-㎛ metamorphic high electron mobility transistor and fabricated a W-band monolithic microwave integrated circuit chipset with our in-house technology to verify the performance and usability of the developed technology. The DC characteristics were a drain current density of 747 mA/mm and a maximum transconductance of 1.354 S/mm; the RF characteristics were a cutoff frequency of 210 GHz and a maximum oscillation frequency of 252 GHz. A frequency multiplier was developed to increase the frequency of the input signal. The fabricated multiplier showed high output values (more than 0 dBm) in the 94 GHz-108 GHz band and achieved excellent spurious suppression. A low-noise amplifier (LNA) with a four-stage single-ended architecture using a common-source stage was also developed. This LNA achieved a gain of 20 dB in a band between 83 GHz and 110 GHz and a noise figure lower than 3.8 dB with a frequency of 94 GHz. A W-band image-rejection mixer (IRM) with an external off-chip coupler was also designed. The IRM provided a conversion gain of 13 dB-17 dB for RF frequencies of 80 GHz-110 GHz and image-rejection ratios of 17 dB-19 dB for RF frequencies of 93 GHz-100 GHz.

• Journal of Navigation and Port Research
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• v.28 no.3
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• pp.213-219
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• 2004

In this paper, a LNA(Low Noise Amplifier) has been developed, which is operating at L-band i.e., 1452∼1492 MHz for satellite DAB(Digital Audio Brcadcasting) receiver. The LNA is designed to improve input and output reflection coefficient and VSWR(Voltage Standing Wave Ratio) by balanced amplifier. The LNA consists of low noise amplification stage and gain amplification stage, which make a using of GaAs FET ATF-10136 and VNA-25 respectively, and is fabricated by hybrid method. To supply most suitable voltage and current, active bias circuit is designed Active biasing offers the advantage that variations in $V_P$ and $I_{DSS}$ will not necessitate a change in either the source or drain resistor value for a given bias condition. The active bias network automatically sets $V_{gs}$ for the desired drain voltage and drain current. The LNA is fabricated on FR-4 substrate with RF circuit and bias circuit, and integrated in aluminum housing. As a reults, the characteristics of the LNA implemented more than 32 dB in gain. 0.2 dB in gain flatness. lower than 0.95 dB in noise figure, 1.28 and 1.43 each input and output VSWR, and -13 dBm in $P_{1dB}$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.9
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• pp.987-994
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• 2010

In this paper, a simple and effective active load-pull method is proposed, and the method to improve the efficiency of X-band power amplifier using harmonic control circuit is presented. The proposed active load-pull system mainly consists of directional coupler, phase shifter, short circuit, and power amplifier, and allows a user to access reflection coefficients near the edge of the Smith chart($\Gamma$=1) easily. The device used in this paper is Mitsubishi's GaAs FET MGF1801, and the operating frequency of the power amplifier is 9 GHz, The amplifier had output power of 21.65 dBm and drain efficiency of 24.9 % at class-A, and had output power of 21.46 dBm and drain efficiency of 53.3 % at class-AB. Harmonic control circuit is designed only second and third harmonic components because of the bandwidth limitation of the microwave components. The drain efficiency is improved as much as 6.4 % compared with class-AB power amplifier.

• 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.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.5
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• pp.430-433
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• 2017

This paper presents a S/C/X-band LNA MMIC with resistive feedback structure in 0.25 um GaN HEMT process. The GaN devices have advantages as a high output power device having high breakdown voltage, energy band gap and stability at high temperature. Since the receiver using the GaN device with high linearity can be implemented without a limiter, the noise figure of the receiver can be improved and the size of receiver module can be reduced. The proposed GaN LNA MMIC based on 0.25 um GaN HEMT device is achieved the gain of > 15 dB, the noise figure of < 3 dB, the input return loss of > 13 dB, and the output return loss of > 8 dB in the S/C/X-band. The current consumption of GaN LNA MMIC is 70 mA with the drain voltage 20 V and the gate voltage -3 V.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.4
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• pp.401-410
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• 2014

This paper presents a high-efficiency concurrent dual-band Class-E power amplifier(PA) that is based on a multi-harmonic matching network(MHMN). The proposed MHMN controls the impedance at 1.3 GHz, 2.1 GHz, and their second and third harmonics, respectively, by using transmission lines only rather than switches or lumped components. The dual-band Class-E PA is implemented using Avago ATF-50189 GaAs p-HEMT. The PA exhibits a measured output power of 27.1 dBm and 25.7 dBm, a power gain of 6.1 dB and 4.7 dB, and a drain efficiency of 71.2 % and 60.1 % at 1.3 GHz and 2.1 GHz, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.4
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• pp.440-446
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• 2011

In this paper, a X-band 50 W pulsed solid state power amplifier(SSPA) is designed and fabricated for radar systems. The SSPA consists of a driver amplifier, a high power amplifier, and a pulse modulator. The high power stage employes four 25 W GaAs FET to deliver 50 W at X-band. To meet the stringent target specification for the SSPA, we used a new hybrid pulse switching method, which combine the advantage of pulse modulation and bias switching method. The fabricated SSPA shows a power gain of 44.2 dB, an output power of 50 W over a 1.12 GHz bandwidth. Also, pulse droop < 1 dB meet the design goals and a rise/fall time is less than 12.45 ns. Fabricated X-band pulsed SSPA size is compact with overall size of $150{\times}105{\times}30\;mm^3$.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.623-624
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• 2006

In this paper, we introduce the design and fabrication of V-band power amplifier MMIC with excellent gain-flatness for IEEE 802.15.3c WPAN system. The V-band power amplifier was designed using ETRI' $0.12{\mu}m$ 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 gains of the each stages of the amplifier were modified to have broadband characteristics of input/output matching for first and fourth stages and get more gains of edge regions of operating frequency range for second and third stages in order to make the gain-flatness of the amplifier excellently for wide band. The performances of the fabricated 60 GHz power amplifier MMIC are operating frequency of $56.25{\sim}62.25\;GHz$, bandwidth of 6 GHz, small signal gain ($S_{21}$) of $16.5{\sim}17.2\;dB$, gain flatness of 0.7 dB, an input reflection coefficient ($S_{11}$) of $-16{\sim}-9\;dB$, output reflection coefficient ($S_{22}$) of $-16{\sim}-4\;dB$ and output power ($P_{out}$) of 13 dBm. The chip size of the amplifier MMIC was $3.7{\times}1.4mm^2$.