• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.6A
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• pp.697-704
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• 2004

This paper describes the design and fabrication of an MMIC variable gain LNA for 5GHz wireless LAN applications, using 0.5${\mu}{\textrm}{m}$ gate length GaAs MESFET transistors. The advantages of high gain and low noise performance of E-MESFETS and excellent linear performance of D-MESFETS are combined as a cascode topology in this design. Behavioral model equations are derived from the MESFET nonlinear current voltage characteristics by using Turlington's asymptote method in a cascode configuration. Using the behavioral model equations, a 4${\times}$50${\mu}{\textrm}{m}$ E-MESFET as a common source amplifier and a 2${\times}$50${\mu}{\textrm}{m}$ D-MESFET as a common gate amplifier are determined for the cascode amplifier. The fabricated variable gain LNA shows a noise figure of 2.4dB, variable gain range of more than 17dB, IIP3 of -4.8dBm at 4.9GHz, and power consumption of 12.8mW.

• Journal of Navigation and Port Research
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• v.27 no.4
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• pp.443-447
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• 2003

In this work. using 0.2 GaAs modulation doped FET(MODFET), a high performance DBS downconverter MMIC was developed for direct broadcasting satellite (DBS) application. Without LNA, the downconverter MMIC showed a very low noise of 4.8 dB, which is lower by 3 dB than conventional ones. A low LO power of -10 dBm was required for the normal DBS operation of the downconverter MMIC. which reduced the power consumption via a removal of LO amplifier on MMIC. It required only a low power consumption of 175 mW, which is lower than 70 percent of conventional ones. The LO leakage power at IF output was suppressed to a lower level than 30 dBm, which removes a bulky LO rejection filter on a board. The fabricated chip, which include a mixer, If amplifiers. LO rejection filter, and active balun, exhibited a small size of $0.84{\times}0.9\textrm{mm}^2$.

• 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.23 no.5
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• pp.606-612
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• 2012

A highly efficient multi-mode balanced power amplifier(PA) structure is proposed for W-CDMA handset applications. The proposed PA has 2-stage amplifier configuration and the stage-bypass and load impedance switching techniques were applied to enhance power efficiency at medium power level as well as low output power level. Using the two techniques, four highly efficient power modes were realized. To demonstrate the usefulness of the proposed structure, a GaAs HBT balanced PA module was designed, fabricated, and measured.

• Journal of electromagnetic engineering and science
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• v.9 no.2
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• pp.98-104
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• 2009

An InGaP/GaAs MMIC LC VCO designed with Harmonic Noise Frequency Filtering(HNFF) technique is presented. In this VCO, internal inductance is found to lower the phase noise, based on an analytic understanding of phase noise. This VCO directly drives the on-chip double balanced mixer to convert RF carrier to IF frequency through local oscillator. Furthermore, final power performance is improved by output amplifier. This paper presents the design for a 1.721 GHz enhanced LC VCO, high power double balance mixer, and output amplifier that have been designed to optimize low phase noise and high output power. The presented asymmetric inductance tank(AIT) VCO exhibited a phase noise of -133.96 dBc/Hz at 1 MHz offset and a tuning range from 1.46 GHz to 1.721 GHz. In measurement, on-chip down-converter shows a third-order input intercept point(IIP3) of 12.55 dBm, a third-order output intercept point(OIP3) of 21.45 dBm, an RF return loss of -31 dB, and an IF return loss of -26 dB. The RF-IF isolation is -57 dB. Also, a conversion gain is 8.9 dB through output amplifier. The total on-chip down-converter is implanted in 2.56${\times}$1.07 mm$^2$ of chip area.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.1
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• pp.84-92
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• 2000

A GaAs MESFET MMIC transmitter for 2.4 GHz wireless local loop handset is designed and fabricated. The transmitter consists of a double balanced active mixer and a two stage driver amplifier with voltage negative feedback. In particular, a pair of CS-CG(common source-common gate) structure compensates the reduction in dynamic range caused by unbalanced complementary IF input signals. And to suppress the leakage local power at RF port, the mixer is designed by using phase characteristic between the ports of MESFET. At the bias condition of 2.7 V and 55.2 mA, the fabricated MMIC transmitter with chip dimensions of $0.75\times1.75 mm^2$ obtains a measured conversion gain of 38.6 dB, output $P_{idB}$ of 11.6 dBm, and IMD3 at -5 dBm RF output power of -31.3 dBc. This transmitter is well suited for WLL handset.

• Journal of IKEEE
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• v.26 no.3
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• pp.456-461
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• 2022

In this paper, a two-stage single-ended power amplifier (PA) with broadband gain characteristics was presented by utilizing a radio frequency (RF) transformer (TF), which is essential for a differential amplifier. The bandwidth of a PA can be improved by designing TF to have broadband characteristics and then applying it to the inter-stage matching network (IMN) of a PA. For broadband gain characteristics while maintaining the performance and area of the existing PA, an IMN was implemented on an monolithic microwave integrated circuit (MMIC) and a multi-layer printed circuit board (PCB), and the simulation results were compared. As a result of simulating the PA module designed using InGaP/GaAs HBT model, it has been confirmed that the PA employing the proposed design method has an improved fractional bandwidth of 19.8% at a center frequency of 3.3GHz, while the conventional PA showed that of 11.2%.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.10
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• pp.159-168
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• 2012

In this paper, a W-band single-chip receiver MMIC for FMCW(Frequency-modulated continuous-wave) radar is presented using $0.15{\mu}m$ GaAs pHEMT technology. The receiver MMIC consists of a 4-stage low noise amplifier(LNA), a down-converting mixer and a 3-stage LO buffer amplifier. The LNA is designed to exhibit a low noise figure and high linearity. A resistive mixer is adopted as a down-converting mixer in order to obtain high linearity and low noise performance at low IF. An additional LO buffer amplifier is also demonstrated to reduce the required LO power of the W-band mixer. The fabricated W-band single-chip receiver MMIC shows an excellent performance such as a conversion gain of 6.2 dB, a noise figure of 5.0 dB and input 1-dB compression point($P_{1dB,in}$) of -12.8 dBm, at the RF frequency of $f_0$ GHz, LO input power of -1 dBm and IF frequency of 100 MHz.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.4
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• pp.17-26
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• 1997

A enw channel current model of GaAs MeSFET suitagle for applications to microwave CAD has been developed. The current model includes the bias-dependent frequency dispersion effects and its parameters are extracted from the pulsed I-V measurements at several quiescent bias points. The model is verified by applying to the nonlinear circuit designs of power amplifier and MMIC mixer.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.921-924
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• 2005

We report low conversion loss and high LO to RF isolation 94 GHz MMIC resistive mixers based on 0.1 ${\mu}m$ InGaAs/InAlAs/GaAs metamorphic HEMT technology. The fabricated resistive mixers applied a one-stage amplifier on RF port of the mixer. By using the one-stage amplifier, we obtained the decrement of conversion loss and the increment of LO to RF isolation. So, we can obtain higher performances than conventional resistive mixers. The modified mixer shows excellent conversion loss of 6.7 dB at a LO power of 10 dBm. We also observed an extremely high isolation characteristic from the MMICs exhibiting the LO-RF isolation of 21 ${\pm}$ 0.5dB in a frequency range of 93.7${\sim}$ 94.3 GHz. The low conversion loss and high LO-RF isolation characteristics of the MMIC modified resistive mixers are mainly attributed to the performance of the MHEMTs exhibiting a maximum transconductance of 654 mS/mm, a current gain cut-off frequency of 173 GHz and a maximum oscillation frequency of 271 GHz.