• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.2
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• pp.67-73
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• 2010

We have developed a millimeter-wave passive imaging system with reflector for detection of concealed objects. We have designed a millimeter-wave sensor, control device for reflector control, and a lens for focusing of millimeter-wave signal at center frequency of 94GHz. DC signal from millimeter-wave sensor output is filtered by low pass filter and amplified by video amplifier, and then converted into digital signal by using ADC/DAQ. This signal is image processed by computer, and it is possible to obtain millimeter-wave passive image with resolution of $18{\times}64$ pixel using the fabricated system. It is shown that we can obtain the image of men and concealed object with the system.

• International journal of advanced smart convergence
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• v.8 no.4
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• pp.34-39
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• 2019

Millimeter-wave (mmWave) and Non-orthogonal multiple access (NOMA) are expected to be the major techniques that lead to the next generation wireless communication. NOMA provides a high spectrum efficiency by sharing of spatial resources among users in the same frequency band. Meanwhile, millimeter-wave gives a huge underutilized bandwidth at extremely high frequency band (EHF) which covers 30GHz to 300GHz. These techniques have been proven in several recent literatures to achieve high data rates. The combination of NOMA and millimeter-wave techniques further improves average sum capacities, as well as reduces the interference compared to conventional wireless communication systems. In this paper, we focus on hybrid NOMA system working in millimeter-wave frequency. We propose a clustering algorithm used for a hybrid NOMA scheme to optimize the usage of wireless resources. The proposed clustering algorithm adds several conditions in grouping users and defining clusters to increase the probability of the successful superposition decoding process. The performance of the proposed clustering algorithm is investigated in hybrid NOMA system and compared with the conventional orthogonal multiple access (OMA) scheme.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.3 s.357
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• pp.105-110
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• 2007

We have built the millimeter-wave passive imaging system with a lens and mechanical scan antenna. The lens was designed based on optical theory in order to focus millimeter-wane. A full image was taken from image points scanned by Placing antenna at the representative focal plane selectively. An integrated antenna array device for low-loss and low-noise with the array of 4 by 1, where components such as antenna, balun, MMIC, and detector were assembled on a sin91e substrate, and a fermi tapered slot antenna with high-gain and low-side lobe were used for elements of this millimeter-wave passive imaging system. Two dimensional antenna arrangement on focal plane was achieved in this imaging system.

• 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 Advanced Navigation Technology
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• v.13 no.4
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• pp.544-550
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• 2009

In this paper, we proposed the radio wave propagation characteristics of the next-generation ultrafast wireless communication system in millimeter-wave fading channel. For considering doppler shift and Rayleigh fading simultaneously, the fading simulator of Jakes model implemented and analyzed the performance of the next-generation wireless communication system. In addition, the error rate characteristics of DS-CDMA system analyzed in the millimeter-wave fading channel and the system performance improved by coding technique and diversity technique.

• JSTS:Journal of Semiconductor Technology and Science
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• v.5 no.3
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• pp.210-219
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• 2005

We report on a low-cost V-band wireless transceiver with no use of any local oscillator in the receiver block using a self-heterodyne architecture. V-band millimeter-wave monolithic IC (MMIC) modules were developed to demonstrate the wireless transceiver using coplanar waveguide (CPW) and GaAs PHEMT technologies. The MMIC modules such as the MMIC low noise amplifier (LNA), medium power amplifier (MPA) and the up/down-mixer were installed in the transceiver system. To interface the MMIC chips with the component modules for the transceiver system, CPW-to-waveguide fin-line transition modules of WR-15 type were designed and fabricated. The fabricated LNA modules showed a $S_{21}$ gain of 8.4 dB and a noise figure of 5.6 dB at 58 GHz. The MPA modules exhibited a gain of 6.9 dB and a $P_{1dB}$ of 5.4 dBm at 58 GHz. The conversion losses of the up-mixer and the down-mixer module were 14.3 dB at a LO power of 15 dBm, and 19.7 dB at a LO power of 0 dBm, respectively. From the measurement of V-band wireless transceiver, a conversion gain of 0.2 dB and a $P_{1dB}$ of 5.2 dBm were obtained in the transmitter block. The receiver block showed a conversion gain of 2.1 dB and a $P_{1dB}$ of -18.6 dBm. The wireless transceiver system demonstrated a successful data transfer within a distance of 5 meters.

• Proceedings of the IEEK Conference
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• 2001.06e
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• pp.25-28
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• 2001

This paper introduce a millimeter-wave radar system. As Fig 1 shows, This system consists of millimeter-wave radar front-end and digital signal processing parts through receive waves regarding up-coming obstacles. The system works as follow process; (1) Generate regular tripodal waves using the FMCW pulse generator (2) Transmit/Receive waves regarding up-coming obstacles (3) Analog filtering (4) FIFO memory interface (5) FFT(Fast Fourier Transform) (6) Calculation of distance / speed between cars (7) Object display and calibration. We have progress to solve the problem like as increase of traffic accidents causing damage and injuries due to the increased number of motor vehicles and long distance driving, and Need for a device to help drivers who are in trouble due to bad weather conditions. We are expect to Take the lead as a core technology in the ITS industry and to develop circuit and signal processing technologies related to millimeter-wave bandwidth.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.5 s.347
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• pp.182-188
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• 2006

In this study, we have designed the millimeter-wave passive imaging system which records energy that is reflected or emitted from the source and produces image. The lens and front-end of receiver appeared to be important in the system to detect input thermal noise signal. The lens for signal focusing has been designed by optical transfer function. Amplifier of the imaging systemhas been set up with 40dB in maximum gain, 5 dB in maximum noise figure, and 10GHz in bandwidth to enhance sensitivity for thermal noise and to receive it in wide-band width as well. The SBD MSS-20 141B10D diode has been used for the detector circuit to convert amplified millimeter-wave signals to DC output.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.575-578
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• 2005

We report on a low-cost V-band wireless transceiver with no use of any local oscillator in the receiver block using a self-heterodyne architecture. V-band Microwave monolithic IC (MMIC) modules were developed to demonstrate the wireless transceiver using coplanar waveguide (CPW) and GaAs PHEMT technologies. The MMIC modules such as the MMIC low noise amplifier (LNA), medium power amplifier (MPA) and the up/down-mixer were installed in the transceiver system. To interface the MMIC chips with the component modules for the transceiver system, CPW-to-waveguide fin-line transition modules of WR-15 type were designed and fabricated. The fabricated LNA modules showed a $S_{21}$ gain of 8.4 dB and a noise figure of 5.6 dB at 58 GHz. The MPA modules exhibited a gain of 6.9 dB and a $P_1$ $_{dB}$ of 5.4 dBm at 58 GHz. The conversion losses of the up-mixer and the down-mixer module were 14.3 dB at a LO power of 15 dBm, and 19.7 dB at a LO power of 0 dBm, respectively. From the measurement of V-band wireless transceiver, a conversion gain of 0.2 dB and a P $_{1dB}$ of 5.2 dBm were obtained in the transmitter block. The receiver block showed a conversion gain of 2.1 dB and a P $_{1dB}$ of -18.6 dBm. The wireless transceiver system demonstrated a successful data transfer within a distance of 5 meters.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.3 s.357
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• pp.111-116
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• 2007

We have developed a passive millimeter wave (PMMW) imaging system with two-dimensional imaging arrays. For the imaging system we achieved single-substrate imaging-array element which include all necessary component such as Fermi tapered slot antenna (TSA), a balun, LNA's and a detector circuit on it. Two-dimensional arrays for real-time imaging at the 35 GHz band are currently under development. We will be able to make an advanced PMMW image system based on our system with the $2\times2$ imaging array in the near future.