• Journal of Astronomy and Space Sciences
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• v.30 no.3
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• pp.123-125
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• 2013

2FGL J1823.8+4312 and 2FGL J1304.1-2415 are two unidentified Fermi objects which are associated with cluster of galaxies. In order to exam the possibility of cluster of galaxies as gamma-ray emitters, we search for counterpart of these two unidentified Fermi objects in other wavebands. However, we find other candidate to be more likely the counterpart of the unidentified Fermi object for both sources. We compare their light curves and SEDs in order to identify their source types. However, data at millimeter and sub-millimeter wavebands, which is important for us to constrain the SED at synchrotron peak, is lacking of measurement. Therefore, we proposed to SMA observation for these two sources. We have got data and are doing further analysis.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.12
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• pp.2386-2391
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• 2011

Tracking and detecting targets by the millimeter wave seeker is affected by moving of platform. In order to perform the tracking performance, stabilization of a millimeter wave seeker which consists of 2-axis gimbals was considered in this study. The feasibility of the analysis and the 2-axis gimbal servo system modeling design were verified along with some simulation results.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.3 no.2 s.5
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• pp.85-93
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• 2004

In this paper, microstrip stepped-impedance hairpin resonator (SIR) lowpass filter f.PF) by surface rnicromachining on GaAs substrate is sugsested. This filter has the advantages of compact side, easy fabrication, and sharp cutoff frequency response. The new SIR LPF shows the 3 dB passband of dc to 33 GHz, the insertion loss of 0.82 dB, and the return loss of better than 17 dB up to 25.57 GHz. This filter is useful for many microwave system applications.

• 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.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.6
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• pp.1334-1340
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• 2003

In this paper, We have proposed an Heterodyne technique to generate millimeter-wave signal. Microwave signals in cellular broadband mobile communication networks and distributed networks can favorably be generated and distributed by optical techniques. In principle, these techniques have already been investigated for optical control of phase- array antennas, characterization of photo-detector and phase locking of millimeter-wave oscillators and now being applied to wireless communications. The generation and transmission of millimeter-wave radio signals by optical means is of interest for future pico-cell broadband mobile communication system, especially for systems operating at frequencies of 300Hz.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2000.11a
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• pp.197-201
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• 2000

In this paper, a MMIC(Monolithic Microwave Integrated Circuit) broadband drive amplifier for wireless communication system has designed using active feedback method. The MMIC brodband amplifier was designed using 0.5$\mu\textrm{m}$ MESFET of ETRI library. Simulation results show that gain is 22 dB, and gain flatness ${\pm}$1 dB. Maximum output power 15 dBm and noise figure 2.5 dB in bandwidth 500 MHz ～3.0 GHz. The MMIC Broadband amplifer's chip area is 14mm${\times}$1.4mm.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.151-154
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• 1999

In this paper, we showed parasitic effects in the millimeter wave package, and proposed a suppression method of parasitic effects using Si lossy layer. From CB-CPW used as a transmission line of the MIMIC package, PPL mode is generated and this causes the parasitic effects considered from this paper. Parasitic effects caused by PPL mode such as resonance, radiation, and crosstalk in the single and multi-chip package ran affect to the performance of MIMIC seriously. To suppress these parasitic effects, we adapted Si lossy layer $\rho$ . The PPL mode can be suppressed by the lossy layer, and it eliminates the parasitic effects. It is expected that showed results ran be used as luxurious data for design MIMICs and various types of millimeter wave applications.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.12
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• pp.1700-1705
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• 2013

A second harmonic millimeter wave oscillator utilizing sub-harmonic injection-synchronization is presented. A 8.7GHz oscillator with MES-FET is designed, and is driven as a harmonic output oscillator at 17.4GHz by means of sub-harmonic injection-synchronization. The oscillator operates as a multiplier as well as a oscillator in this scheme. Adopting this method, a high sable, high frequency millimeter wave source is obtainable even though self-oscillating frequency of an oscillator is relatively low. The range of injection-synchronization is about 26MHz, and is proportional to the input sub-harmonic power. The spectrum analysis of the 2nd harmonic output frequency shows remarkably decreased the phase noise level.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.365-368
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• 2007

Millimeter-wave (MMW) imaging radiometer systems have an attractive advantage to obtain an image through low visibility weather conditions such as fog, clouds and light rain compared with visible and infrared imaging systems. Many countries have developed a various kinds of MMW imaging radiometers for the aim of low cost and high performance. In Korea, Millimeter-wave Imaging RAdiometer Equipment (MIRAE) has been developed since the end of 2006. Recently the development of some modules was finished for the test model. This paper describes the design and development of the MIRAE. In addition, the test results of its manufactured modules are presented.

• Electronics and Telecommunications Trends
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• v.33 no.5
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• pp.1-12
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• 2018

One of the most remarkable aspects of the recently completed 3GPP release-15 (5G new radio phase 1) is the fact that some millimeter-wave bands have been officially approved for 5G mobile communications. Because the demand for higher transmission capacity has only grown, other millimeter-wave or even higher-frequency terahertz-wave bands have attracted more attention over time. Based on this effort, this paper reviews and discusses the existing technologies and their trends in high-frequency circuits and systems at the millimeter and terahertz-wave bands, particularly for future mobile communications.