• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.1
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• pp.117-122
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• 2006

A CMOS LNA based on a single-stage cascode configuration is designed for MB-OFDM ultra-wide band(UWB) systems. Wideband($3.1GHz\~4.9GHz$) input matching is performed using a simple bandpass filter to minimize the chip size and the noise figure degradation. The simulation results using $0.18{\mu}m$ CMOS process parameters show a power gain of 9.7dB, a 3dB band width of $2.1GHz\~7.1GHz$, a minimum NF of 2dB, an IIP3 of -2dBm. better than -11.8dB of input matching while occupying only $0.74mm^2$ of chip area. It consumes 25.8mW from a 1.8V supply.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.12
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• pp.77-84
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• 2007

In this parer, a wideband low-noise amplifier (LNA) has been realized in a 0.18mm CMOS technology for the applications of subsampling direct-conversion RF receivers. By exploiting the inverter-type transimpedance input stage with a 3rd-order Chebyshev matching network, the wideband LNA demonstrates the measured results of the -3dB bandwidth of 5.35GHz, the power gain (S21) of $12\sim18dB$, the noise figure (NF) of $6.9\sim10.8dB$, and the broadband input/output impedance matching of less than -10dB/-24dB within the bandwidth, respectively. The chip dissipates 32.4mW from a single 1.8V supply, and occupies the area of $0.56\times1.0mm^2$.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.2
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• pp.212-216
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• 1999

SiC(3C) photodiodes (PDs) were fabricated on p-type Si(111) substrates using chemical vapor deposition (CVD) technique by pyrolyzing tetramethylsilane (TMS) with $H_{2}$ carrier gas. Electrical properties of SiC(3C) were investigated by Hall measurement and current-voltage (I-V) characteristics. SiC(3C) layers exhibited n-type conductivity. Ohmic contact was formed by thermal evaporation Al metal through a shadow-mask. The optical gain $(G_{op})$ of the SiC(3C)/Si PD was measured as a function of the incident wavelength. For the analysis of the photovoltaic detection of the Sic(3C) n/p PD, the spectral response (SR) has calculated by using the electrical parameters of the SiC(3C) layer and the geometric structure of the PD. The peak response calculated for properly chosen parameters was about 0.75 near 550 nm. We expect a good photoresponse in the SiC(3C) heterostructure for the wavelength range of 400~600 nm. The SiC(3C) photodiode can detect blue and near ultraviolet (UV) radiation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.6
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• pp.1057-1062
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• 2016

In this paper, a design method for a compact log-perio dic half-bow-tie dipole array antenna for an operation in a UWB band(3.1-10.6 GHz) is studied. The proposed antenna is miniaturized by using half-bow-tie shaped dipole elements instead of strip-type dipole elements, which are commonly used in a general log-periodic dipole array(LPDA) antenna, and by reducing the element spacing. The effects of the flare angle of the half-bow-tie elements and the spacing factor on input reflection coefficient and realized gain characteristics of the proposed log-periodic antenna are analyzed. The optimized antenna is fabricated on an FR4 substrate, and the experiment results show that the antenna has a frequency band of 2.95-11.31 GHz for a VSWR < 2, which assures the operation in the UWB band. In addition, the length and width of the proposed antenna are reduced to 32.1 % and 18.3 %, respectively, compared to the LPDA antenna.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.3
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• pp.330-333
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• 2016

In this paper, we propose 77 GHz power amplifier for long range automotive collision avoidance radar using 65 nm CMOS process. The proposed circuit has a 3-stage single power amplifier which includes common source structure and transformer. The measurement results show 18.7 dB maximum voltage gain at 13 GHz 3 dB bandwidth. The measured maximum output power is 10.2 dBm, input $P_{1dB}$ is -12 dBm, output $P_{1dB}$ is 5.7 dBm, and maximum power add efficiency is 7.2 %. The power amplifier consumes 140.4 mW DC power from 1.2 V supply voltage.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.3
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• pp.269-276
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• 2016

This paper presents a 2.65 GHz Doherty power amplifier with internally-matched GaN HEMT. Internal matching circuits were adopted to match its harmonic impedances inside the package. Simultaneously, due to the partially matched fundamental impedance, input and output matching networks become simpler. Bond wires and parasitic elements of transistor package were predicted by EM simulation. For the LTE signal with 6.5 dB PAPR, the implemented Doherty power amplifier shows a power gain of 13.0 dB, a saturated output power of 55.4 dBm, an efficiency of 49.1 %, and ACLR of -26.3 dBc at 2.65 GHz with an operating voltage of 48 V.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.5
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• pp.397-400
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• 2018

This paper presents a miniaturized 65 nm CMOS 30~46 GHz wideband amplifier. To minimize the chip area, coupled inductors are used in the matching networks. The measurement shows that the fabricated amplifier exhibits 9.3 dB of peak gain, 16 GHz of 3 dB bandwidth, and 42 % fractional bandwidth. The measured input and output return losses were more than 10 dB at 35.8~46.0 GHz and 28.6~37.8 GHz, respectively. The chip consumes 42 mW at 1.2 V. The measured group delay variation is 19.1 ps within the 3 dB bandwidth and the chip size excluding the pads is $0.09mm^2$.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.4
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• pp.86-93
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• 2008

A low-power, low-noise, highly-linear hybrid balun circuit is proposed for 2.4-GHz fully differential CMOS direct conversion receivers. The hybrid balun is composed of a passive transformer and loss-compensating auxiliary amplifiers. Design issues regarding the optimal signal splitting and coupling between the transformer and compensating amplifiers are discussed. Implemented in $0.18{\mu}m$ CMOS process, the 2.4 GHz hybrid balun achieves 2.8 dB higher gain and 1.9 dB lower noise figure than its passive counterpart and +23 dBm of IIP3 only at a current consumption of 0.67 mA from 1.2 V supply. It is also examined that the hybrid balun can remarkably lower the total noise figure of a 2.4 GHz fully differential RF receiver only at a cost of 0.82 mW additional power dissipation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.8
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• pp.1465-1470
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• 2006

This paper presents a design of low power CMOS LNA(Low Noise Amplifier) for 2.4 GHz ZigBee applications that is a promising international standard for short area wireless communications. The proposed circuit has been designed using TSMC $0.18{\mu}m$ CMOS process technology and two stage cascade topology by current reuse technique. Two stage cascade amplifiers use the same bias current in the current reused stage which leads to the reduction of the power dissipation. LNA design procedures and the simulation results using ADS(Advanced Design System) are presented in this paper. Simulation results show that the LNA has a extremely low power dissipation of 1.38mW with a supply voltage of 1.0V. This is the lowest value among LNAs ever reported. The LNA also has a maximum gain of 13.38dB, input return loss of -20.37dB, output return loss of -22.48dB and minimum noise figure of 1.13dB.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.406-409
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• 2003

In this paper, a 4-wavelength optical transceiver system is designed and implemented by using TFF (thin film filter) type OADMs (optical add-drop multiplexers). In this new system, the wavelengths of 1510 nm and 1530 nm are used for uploa and download signals, respectively, as well as the wavelengths of 1550 nm and 1310 nm which have been utilized in a 2-wavelength optical transceiver systems. The 4-wavelength optical module show pass characteristics of -1.6 dBm, -1.7 dBm, -5.6 dBm, -5.8dBm for 1510nm, 1530 nm, 1550 nm, 1570 nm, respectively, with 1.2 dBm of input laser power. The isolation for characteristics of the optical module for all the wavelengths are less than -40dB, which is very acceptable for filed requirements.