• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.675-678
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• 1998

In this paper, power amplifiers for PCS phone were designed with the GEC Marconi H40 HEMT libray. The 1st stage was carefully designed in order to obtain k〉1 using a parallel resistor, and its S21 gain of 18.3dB and input reflection coefficient of -4dB were obtained. And S21 gain of 18dB and input reflection coefficient of -7dB were obtained from the 2nd stage. Finally, total S21 gain of 38dB, input reflection coefficient of -16dB, power gain of 35.2dB, output power of 28.7dBm and PAE(power added efficiency) of 29% were obtained from the designed MMIC power amplifiers. The chip size is $1.729$\times$0.94\textrm{mm}^2.$

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.5
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• pp.1-10
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• 1998

A GaAs MMIC composed of VCO (voltage controlled oscillator) and mixer for PCS receiver has been developed using 1.mu.m ion implanted GaAs MESFET process. The VCO consists of a colpitts-type oscillator with a dielectric resonator and the circuit configuration of the mixer is a dual-gate type with an asymmetric combination of LO and RF FETs for the improvement of intermodulation characteristics. The common-source self-biasing is used in all circuits including a buffer amplifier and mixer, achieving a single power supply (3V) operation. The total power dissipation is 78mW. The VCO chip shows a phase noise of-99 dBc/Hz at 100KHz offset. The combined VCO/mixer chip shows a flat conversion gain of 2dB, the frequency-tuning factor of 80MHz/volts in the varacter bias ranging from 0.5V to 0.5V , and output IP3 of dBm at varactor bias of 0V. The fabricated chip size is 2.5mm X 1.4mm.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2000.11a
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• pp.146-149
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• 2000

SiGe HUT뜰 이용하여 Cellular 주파수 대역(824-849 MHz)에서 MMIC 상향 주파수 혼합기와 가변이득 증폭기를 설계하였다. 동작 전압은 2.7 V 이며, 이중평형 구조의 상향 주파수 혼합기는 12 dB의 변환이득, -0.6 dBm의 1dB 이득압축 출력전력, 30 dB 이상의 LO-RF 단자 격리도 특성, 1.25의 LO-VSWR. 1.34의 RF-VSWR을 가지며, 상호컨덕턴스형 가변이득 증폭기는 35 dB의 최대 선형이득, 13 dBm의 1dB 이득압축 출력전력, 42dB의 가변이득, 23dB의 3차 상호변조 교점 출력전력(OIP$_3$), 1.27의 입력 VSWR, 1.1의 출력 VSWR 특성을 보인다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.6
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• pp.175-181
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• 2019

For the purpose of Application to the small radar sensor, the MMIC Chip, which is the core component of the W-band, was designed in Korea according to the characteristics of the transceiver and manufactured by 0.1㎛ GaAs pHEMT process, and compared with the MMIC chip purchased overseas. The noise figure of low noise amplifier, insertion loss of the switch and image rejection performance of the down-converted mixer MMIC chip showed better characteristics than those of commercial chips. The MMIC chip developed in domestic was applied to the transmitter and receiver through W-band waveguide low loss transition structure design and impedance matching to verify the performance after the fabrication is 9.17 dB, which is close to the analysis result. As a result, it is judged that the transceiver can be applied to the small radar sensor better than the MMIC chip purchased overseas.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.9
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• pp.13-20
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• 1999

A 2-stage MMIC(monolithic Microwave Integrated Circuits) LNA(Low Noise Amplifiers) at 30GHz hand has been designed and fabricated for the Ka-band Satellite Communications. The $0.15 {\mu}m$ with the width of $80 {\mu}m$ pHEMT technology was used for the fabrication of this MMIC LNA. Using the series feedback technique, ultra low noise and excellent S11 could be obtained at the same time without the cost of gain at 30GHz-band. The stability factors(Ks) for each stage and overall stage are greater than 1 at full frequency bands by the bias circuits and stabilization circuit. The measured performances, which agree well with the predicted performances, show this 2-stage MMIC LNA has the gain of more than 15.7dB and noise figure of less than 2.09dB over 29GHz to 33GHz.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.3 no.1
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• pp.11-19
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• 1992

To design of Ultra-wideband amplifier, we analyzed the inductor peaking to reduce the capacitance effect of GaAs MESFET in upper frequency edge. And we deduced an optimun inductor peaking element from transfer function of GaAs MESFET small-signal equivalent circut and realized the Feedback Amplifier Module (FAM) having flat gain. We design the imput and output impe dance matching networks by Real-Frequency Method. It show that the gain of designed amplifier has a 6.38dB with gain variation 0.56 at 0.1~12 GHz frequency gand by computer simu-lation.

• ETRI Journal
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• v.36 no.3
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• pp.498-501
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• 2014

A C-band 50 W high-power microwave monolithic integrated circuit amplifier for use in a phased-array radar system was designed and fabricated using commercial $0.25{\mu}m$ AlGaN/GaN technology. This two-stage amplifier can achieve a saturated output power of 50 W with higher than 35% power-added efficiency and 22 dB small-signal gain over a frequency range of 5.5 GHz to 6.2 GHz. With a compact $14.82mm^2$ chip area, an output power density of $3.2W/mm^2$ is demonstrated.

• ETRI Journal
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• v.35 no.4
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• pp.718-721
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• 2013

This letter proposes a novel calibration method for a multiport amplifier (MPA) to achieve optimum port-to-port isolation by correcting both the amplitude and phase of the calibration signals. The proposed architecture allows for the detection of the phase error and amplitude error in each RF signal path simultaneously and can enhance the calibrated resolution by controlling the analog phase shifters and attenuators. The designed $2{\times}2$ and $4{\times}4$ MPAs show isolation characteristics of 30 dB and 27 dB over a frequency range of 19.5 GHz to 22.5 GHz, respectively.

• Journal of the Korea Society of Computer and Information
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• v.11 no.5 s.43
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• pp.267-272
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• 2006

In this paper, an integrated and small Ka-band transceiver module has been developed for measuring distance at the radar systems. Oscillator of cavity type, The MMIC such as VCO, power amplifier, LNA, and mixer, and passive components are integrated on carriers and these are assembled in the transceiver module directly. The test result shows the output power of 21dBm and the noise figure of 5dB using developed transceiver module. Using developed FMCW transceiver module. We can measure the 60m range target by detecting the beat frequency and distinguish both earth and sky using radiometer signal. So we defined that the integrated module using MMIC had a good performance for the radar and radiometer at Ka-band.

• Journal of the Korean Institute of Navigation
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• v.25 no.1
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• pp.53-60
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• 2001

This paper presents the fabrication of the LNA which is operating at 2.13 ~ 2.16 GHz for IMT-2000 front-end receiver using series feedback and resistive decoupling circuit. Series feedback added to the source lead of a GaAs FET keeps the low noise characteristics and drops the input reflection coefficient of a low noise amplifier simultaneously. Also, it increases the stability of the LNA. Resistive decoupling circuit is suitable for input stage matching because a signal at low frequency is dissipated by a resistor in the matching network. The amplifier consists of GaAs FET ATF-10136 for low noise stage and VNA-25 which is internally matched MMIC for high gain stage. The amplifier is fabricated with both the RF circuits and self bias circuit on the Teflon substrate with 3.5 permittivity. The measured results of the LNA which is fabricated using the above design technique are presented more than 30 dB in gain, PldB 17 dB and less than 0.7 dB in noise figure, 1.5 in inputㆍoutput SWR(Standing Wave Ratio).