• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.11
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• pp.1318-1323
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• 2010

A lot of demand for parts of millimeter wave band, as would be expected 57~63 GHz band down conversion mixer was designed and fabricated using IHP 0.25 um SiGe process. Designed and fabricated mixer was double balanced type and located reduced 3D balun at RF port and buffer amplifier at outport for suppression LO signal and conversion gain. Fabricated mixer measured conversion gain of 13.8 dB, $P1dB_{in}$ -17 dBm and 88 mA of current consumption characteristics, respectively.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.8
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• pp.105-111
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• 2004

In this paper, millimeter-wave high gain and broadband MHEMT cascode amplifiers were designed and fabricated. The 0.1 ${\mu}{\textrm}{m}$ InGaAs/InAlAs/GaAs Metamorphic HEMT was fabricated for cascode amplifiers. The DC characteristics of MHEMT are 640 mA/mm of drain current density, 653 mS/mm of maximum transconductance. The current gain cut-off frequency(f$_{T}$) is 173 GHz and the maximum oscillation frequency(f$_{max}$) is 271 GHz. By using the CPW transmission line, the cascode amplifier was designed the matched circuit for getting the broadband characteristics. The designed amplifier was fabricated by the MHEMT MIMIC process that was developed through this research. As the results of measurement, the 1 stage amplifier obtained 3 dB bandwidth of 37 GHz between 31.3 to 68.3 GHz. Also, this amplifier represents the S21 gain with the average 9.7 dB gain in bandwidth and the maximum gain of 11.3 dB at 40 GHz. The 2 stage amplifier has the broadband characteristics with 3 dB bandwidth of 29.5 GHz in the frequency range from 32.5 to 62.0 GHz. The 2 stage cascode amplifier represents the high gain characteristics with the average gain of 20.4 dB in bandwidth and the maximum gain of 22.3 dB at 36.5 GHz.z.z.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.8
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• pp.7-18
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• 1999

We have designed and tuilt the quasioptical system for the dual channel receiver which is used for the simultaneous observation of the cosmic radio with 100GHz band and 150GHz band. The quasioptical system has been widely used to guide the beam for the millimeter and submillimeter waves. A Gaussian distribution of field and power transverse to their axis of propagation allow the simple and elegant theory of Gaussian quasioptics. Using the theory of Gaussian beam, we introduced the analysis of image beam which is applied for a wide range of frequency. In order to guide two beams from the Cassegrain antenna simultaneously, the quasioptical system and its components for the dual channel receiver were designed by using the image beam method. We have checked the characteristics of the quasioptical components and the system by using the heam measurement system, which is made by us. The quasioptical system has been installed in the dual channel receiver on the Cassegrain antenna. The performance of this system has been finally confimed through the successful simultaneous observation with two bands of the cosmic radio.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.5
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• pp.36-41
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• 2007

We report the 94 GHz CPW branch-line bandpass filter for planar integrated millimeter-wave circuits. The branch-line coupler operates as a transversal filtering section by connecting the coupling ports to the open load stubs and taking the isolation port as the output node. For design of the 94 GHz branch-line bandpass filter, we built the CPW library and optimized the characteristic impedances and the lengths of the branch-line coupler and the open load stubs. The fabricated 94 GHz bandpass filter exhibits an insertion loss of 2.5 dB with an 11.7 % 3 dB relative bandwidth and the return loss is -18.5 dB at a center frequency of 94 GHz.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.5
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• pp.63-70
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• 2020

In this paper, the transmit-receive module for military seekers has been designed and fabricated in 35 GHz. To increase the performance of substrates and high integration of circuits in millimeter-wave band, a 4-layer LCP(Liquid Crystal Polymer) substrate was developed. This substrate was implemented with three FCCL substrates and two adhesive layers, and a process using the difference in melting point between the substrates was used for lamination. Using a strip line and a microstrip line was confirmed by the transmission loss along the length of the substrate, and the performance of LCP substrates was validated with a power divider in 35 GHz. After confirming the performance of individual blocks such as power amplifier and low noise amplifier, a single channel Ka-band transmission/reception module was developed using a 4-layer liquid crystal polymer substrate. The transmit power of this module has above 1.1W in pulse duty 10% and has an output power of 1.1W and it has receive noise figure less than 8.5 dB and receive gain more than 17.6 dB.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2009.10a
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• pp.54-55
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• 2009

The bandwidth of detecting radars used for military purpose is increasingly broadened, and recently, the frequency band of the detecting radars is expanding to millimeterwave bands c! the millimeterwave bands of 35 GHz and 94 GHz. Since, especially, it is essential and important to fabricate and develop EM wave absorber with the absorption ability more than 10 dB in 94 GHz band, the EM wave absorber was manufactured based on the design method by FDTD simulation As a result, the developed EM wave absorber with the composition ratio of Binder(CPE with additional materials) : Carbon = 70 : 30 wt.% has the thickness of 0.7 mm and the absorption ability more than 14 dB in the frequency range of 94 GHz.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.5
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• pp.123-129
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• 2023

MIMO antenna is a field in which various researches have been actively conducted for a long time, and its design concept is universally well known. However, Unlike conventional MIMO antennas, MIMO antennas for autonomous driving radars, which have recently been attracting attention, are designed in W-band which is a millimeter wave band, and must also meet novel design conditions to satisfy the performance of autonomous driving radars. Therefore, a novel and different approach is required for the design and beam pattern verification of the MIMO antenna for autonomous driving radar. In this paper, a MIMO antenna is designed and the design process to satisfy the conditions of a W-band autonomous driving radar is introduced, and proposes a beam pattern verification method for a W-band MIMO antenna mounted on an autonomous driving radar system.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.9
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• pp.18-24
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• 2007

We report broadband cascode amplifiers of a single-ended and a balanced amplifier for the millimeter-wave applications. The amplifiers were fabricated using 0.1 ${\mu}m\;{\Gamma}-gate$ PHEMT technology on GaAs substrate. The single-ended cascode amplifier was designed and fabricated by using shunt peaking technology. The fabricated single-ended cascode amplifier shows 3 dB bandwidth of 37 GHz($18.5{\sim}55.5$ GHz) and the maximum $S_{21}$ gain of 9.38 dB. The balanced cascode amplifier using tandem couplers achieves 3 dB bandwidth and the maximum $S_{21}$ gain of 44.5 GHz($21{\sim}65.5$ GHz) and 10.4 dB at 60 GHz, respectively. The 3 dB bandwidth of the balanced cascode amplifier shows 20% lager than the single-ended cascode amplifier.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.11 s.353
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• pp.210-215
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• 2006

In this paper, we develop the PLL system of the local oscillator system using Gunn oscillator VCO for millimeter wave band receiving system. The local oscillator system consists of the $86{\sim}115GHz$ Gunn. diode oscillator part, the RF processing part including the diplexer and the harmonic mixer, and the DPLL system including Gunn modulator and controller. Based on this configuration, we verify the frequency and power stability of the developed local oscillator system. We developed system which applied to DPLL technique instead of the existing analog PLL method to accomplish this purpose. The developed system for this purpose is tested the frequency and power stability for a long time to confirm performance. Since we confirmed this system that had frequency characteristic of within ${\pm}10Hz$, very fine output drift power characteristic of $0.2{\sim}0.3dBm$ and about 200MHz locking range, it verified suitable for cosmic radio receiving system through the test result.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.4
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• pp.1-6
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• 2008

In this paper, millimeter-wave broadband MHEMT (Metamorphic High Electron Mobility Transistor) cascode amplifiers were designed and fabricated. The $0.1{\mu}m$ InGaAs/InAlAs/GaAs MHEMT was fabricated for cascode amplifiers. The DC characteristics of MHEMT are 670 mA/mm of drain current density, 588 mS/mm of maximum transconductance. The current gain cut-off frequency($f_T$) is 139 GHz and the maximum oscillation frequency($f_{max}$) is 266 GHz. To prevent oscillation of the designed cascode amplifiers, a parallel resistor and capacitor were connected to the drain of common gate device. By using the CPW (Coplanar Waveguide) transmission line, the cascode amplifier was designed and matched for the broadband characteristics. The designed amplifier was fabricated by the MHEMT MMIC process that was developed through this research. As the results of measurement, the amplifier was obtained 3 dB bandwidth of 50.37 GHz between 20.76 to 71.13 GHz. Also, this amplifier represents the S21 gain with the average 7.07 dB gain in bandwidth and the maximum gain of 10.3 dB at 30 GHz.