• Title, Summary, Keyword: Multi-band frequency

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A Study on Low Noise Frequency Synthesizer Design with Compact Size for Multi-Band (소형 다대역 저잡음 주파수 합성기 설계에 관한 연구)

  • Kim, Taeyoung;Han, Jonghoon
    • Journal of the Korea Institute of Military Science and Technology
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    • v.20 no.5
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    • pp.673-680
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    • 2017
  • In the proposed paper, we designed low noise frequency synthesizer with compact size for Multi-Band. The proposed frequency synthesizer consists of fundamental frequency band(2 GHz) and harmonic frequency band(4 GHz). To improve the phase noise and spurious level of frequency synthesizer, we analyze how the configuration of frequency synthesizer affect the phase noise and design the multi-band's structure. The implemented frequency synthesizer reduce both the phase noise and spurious level. The phase noise is -92.17 dBc/Hz at 1 kHz frequency offset in 2 GHz and -90.50 dBc/Hz at 1 kHz frequency offset in 4 GHz. All spurious signals including fundamental frequency are suppressed at least 20 dBc than the second harmonic frequency.

Design and analysis of a new composite double negative metamaterial for multi-band communication

  • Hossain, Mohammad Jakir;Faruque, Mohammad Rashed Iqbal;Islam, Mohammad Tariqul
    • Current Applied Physics
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    • v.17 no.7
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    • pp.931-939
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    • 2017
  • In this paper, a double C-shaped structure of double negative composite metamaterial is designed and depicts in configurations that can capable in a multi-band microwave frequency band. The design has achieved relative negative permeability, relative negative permittivity and relative negative refractive index. Analysis and comparison were done by using four configurations of composite metamaterial such as horizontal $1{\times}1$ array and vertical $1{\times}1$ array structures and the horizontal $1{\times}1$ and vertical $1{\times}1$ unit-cell configurations. Multi-band operating frequencies namely, S-band, C-band and X-band have been achieved using all configurations. The proposed metamaterial size is $1.2cm{\times}1.2cm{\times}0.16cm$ which includes all geometrical parameters to fit the design inside the substrate area. Computer Simulation Technology (CST) is adopted to investigate this design where an incident electromagnetic wave travelling along the positive z-axis with an E-field polarized along the y-axis. The results of the proposed metamaterial depict multi-band metamaterial response over the frequency span from 1 to 15 GHz. The effective medium ratio of the metamaterial unit-cell is 7.44. Moreover, the results clearly seen that the single-negative and double-negative metamaterial characteristics of the unit-cell and arrays over the multi-band. The dimensions and scattering parameters of the proposed double C-shaped metamaterial are suitable for the S -band, C-band and X-band applications.

Reconfigurable Multi-Band Mixer for SDR System

  • Kim, Jeong-Pyo;Choi, Jae-Hoon
    • Journal of electromagnetic engineering and science
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    • v.7 no.4
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    • pp.154-160
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    • 2007
  • A reconfigurable multi-band mixer for the SDR system is proposed. The proposed reconfigurable mixer is operated between $850\;MHz{\sim}2\;GHz$, which includes all commercial mobile communication service. Because the varactor diodes are used to select a specific frequency and to adjust the impedance characteristic of the selected frequency band, the proposed reconfigurable mixer can be achieved to similar performance across all of the tuning range. In addition, the designed reconfigurable mixer is applicable for the SDR system since it has a single signal path for the multi-band signals and wide band tuning range.

Earthquake detection based on convolutional neural network using multi-band frequency signals (다중 주파수 대역 convolutional neural network 기반 지진 신호 검출 기법)

  • Kim, Seung-Il;Kim, Dong-Hyun;Shin, Hyun-Hak;Ku, Bonhwa;Ko, Hanseok
    • The Journal of the Acoustical Society of Korea
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    • v.38 no.1
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    • pp.23-29
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    • 2019
  • In this paper, a deep learning-based detection and classification using multi-band frequency signals is presented for detecting earthquakes prevalent in Korea. Based on an analysis of the previous earthquakes in Korea, it is observed that multi-band signals are appropriate for classifying earthquake signals. Therefore, in this paper, we propose a deep CNN (Convolutional Neural Network) using multi-band signals as training data. The proposed algorithm extracts the multi-band signals (Low/Medium/High frequency) by applying band pass filters to mel-spectrum of earthquake signals. Then, we construct three CNN architecture pipelines for extracting features and classifying the earthquake signals by a late fusion of the three CNNs. We validate effectiveness of the proposed method by performing various experiments for classifying the domestic earthquake signals detected in 2018.

Frequency Band Selection for WLAN Using Multiple Bands of 5 GHz/60 GHz (5 GHz/60 GHz 다중대역을 사용하는 WLAN을 위한 대역이동 결정 기법)

  • Jeong, Tae Hun;Jeong, Dong Geun
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.39A no.12
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    • pp.718-728
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    • 2014
  • The multi-band wireless local area network (WLAN) using 60 GHz band and the lower band (typically 2.4 GHz/5 GHz band) can support the very high data rate in short-distance communication using 60 GHz band and the long-distance communication using the lower band. For heightening the efficiency of multi-band WLAN, an band selection scheme is a necessity. In this paper, we propose an effective frequency band selection scheme for multi-band WLANs. By using computer simulation with NS-3, we show the performance of the proposed schemes when the stations suffer from the human blockage and the log-normal shadowing.

Design of Multi-Band VCO with Fast AFC Technique (광대역 고속 AFC 기법을 적용한 다중 대역 VCO의 설계)

  • Ahn, Tae-Won;Yoon, Chan-Geun;Lee, Won-Seok;Moon, Yong
    • Proceedings of the IEEK Conference
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    • pp.983-984
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    • 2006
  • Multi-band VCO with fast response adaptive frequency calibration (AFC) technique is designed in 1.8V $0.18{\mu}m$ CMOS process. The possible operation is verified for 5.8GHz band, 5.2GHz band, and 2.4GHz band using the switchable L-C resonators for 802.11a/b/g WLAN applications. To linearize its frequency-voltage gain, optimized multiple MOS varactor biasing technique is used. In order to operate in each band frequency range with reduced VCO gain, 4-bit digitally controlled switched-capacitor bank is used and a wide-range digital logic quadricorrelator is implemented for fast frequency detector.

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Fractal Microstrip patch Antenna Design and Fabrication for WLAN/WiMax Applications (WLAN/WiMax용 프랙탈 마이크로스트립 패치 안테나설계 및 제작)

  • Kim, Kab-Ki
    • The Journal of Advanced Navigation Technology
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    • v.15 no.6
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    • pp.1008-1014
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    • 2011
  • In this paper, multi-band fractal microstrip patch antenna which is possible for WLAN band and WiMax band is designed and made. For multi-resonance of developed antenna, resonance frequency, impedance matching, polarity and reflection pattern can mad perfectly, then to make satisfied multi-independent frequency three kind of half circle fractal patch is inserted. In the situation continuously happening half circle in designed structure, antennas one of half-circle band is shown.

Design Approach of Q-band Precision Subminiature Coaxial Adaptor Using 3D Simulator and Its Experimental Results (3D 시뮬레이션과 측정값을 이용한 Q-band 정밀 초소형 동축 어댑터의 설계)

  • Wang, Cong;Qian, Cheng;Cho, Won-Yong;Kim, Nam-Young
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.387-388
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    • 2008
  • This paper presents the design approach and test results of the Q-band precision subminiature coaxial adaptor based on transmission line theory using multi-step impedance and air-holes to increase its cutoff frequency. In order to increase the frequency performance, the adaptor is designed with hooked structure, fixing step, multi-air-holes, and outer conductor. The return loss increments due to the hooked structure and multi air-holes are minimized to 2 dB and 1.5 dB, respectively. A VSWR(Voltage Standing Wave Ratio) of <1.2 is obtained from DC to 40 GHz, while guaranteeing the durability of the adaptor from room-temperature$(25^{\circ}C)$ to $120^{\circ}C$.

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A Study on the RF performance analysis for Multi-band Ultra Wide Band Systems (멀티밴드 UWB 시스템의 무선성능 분석에 관한 연구)

  • Choi, Seok;Kim, Gil-Gyeom;Kwack, Jun-Ho;Kim, Hak-Sun
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.12A
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    • pp.951-957
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    • 2003
  • The analysis of RF performance requirement conditions on communication system is critical indicator to predict the performance of system. UWB(Ultra Wide Band) system which the standard is not established yet is difficult to derive the precise system performance requirement condition. Also, there are differences between conventional UWB system and multi-band system about RF performance requirement condition. In this thesis, the differences are analyzed and performance requirement conditions of multi-band UWB system are described on the basis of the differences. Throughput, maximum transmit power, and sensitivity of multi-band UWB system is varied with respect to the number of Sub-Bands. In addition, because of Multi-path effect, if PRF(Pulse Repetition Frequency) is changed, the Multi-path link margin is happened to compensate for Multi-path Energy Loss which is contributed by increasing of the Link Margin. According to Multi-path Margin, the variation of the resistance with respect to sensitivity and interference signal is observed and analyzed through the simulation.

A study on architecture of channel estimation for multi-band OFDM UWB system (멀티밴드 OFDM UWB 시스템을 위한 채널추정 구조에 관한 연구)

  • Lee Yong-Bae;Jeong Jin-Doo;Chong Jong-Wha
    • Proceedings of the IEEK Conference
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    • pp.293-296
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    • 2004
  • This paper proposes an architecture of channel estimation for multi-band OFDM UWB systems presented to IEEE 802.15.3a by Multi-band OFDM alliance(MBOA). The multi-band OFDM (MB-OFDM) systems should have channel estimation for compensation of signal distortion by multi-band channel. The moving-averaging estimation algorithm and multi-band equalization architecture for MB-OFDM UWB systems proposed in this paper was verified by the simulation. Simulation results show that MB-OFDM system with the proposed architecture have the performance improved by about 3.4 dB compared to system with no channel estimation in 0.1$\pi$ phase-rotated channel.

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