• Title/Summary/Keyword: 3 dB bandwidth

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High gain and broad bandwidth antenna design using cylindrical magneto material (원통형 자성체를 이용한 고이득 및 광대역 안테나 설계)

  • Lee, Ji-Chul;Min, Kyeong-Sik
    • Journal of Navigation and Port Research
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    • v.34 no.1
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    • pp.21-26
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    • 2010
  • This paper describes patch antenna design method of antenna high gain and broad bandwidth using cylindrical magneto material around feeding line. Strong current induction method applied combination to generate magnetic fields around feeding line for antenna high gain characteristic and principle of PIFA designed application for design of antenna broadband. In case of single CMM, gain increased 3.96 dB compare with the reference antenna gain however bandwidth characteristic not increased compare with the reference antenna. In case of dual CMM, gain improved about 10 dB compare with the reference antenna and -10 below bandwidth is 700 MHz(50 MHz~750 MHz) with this paper designed high gain characteristic.

The study of the packaging for Ti:LiN$bO_3$optical modulator device and its electrical and optical characteristics (Ti:LiN$bO_3$ 광변조기 소자의 패키징 및 전기.광학적 특성)

  • 윤형도;김성구;이한영;윤대원
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.35D no.6
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    • pp.72-78
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    • 1998
  • An optical modulator Ti:LiNbO$_3$optical waveguide and CPW electrode structure were fabricated. The optical modulator was packaged using components such as ferrules, dirmy LN block and glass, vibration and shock absorbption pad, and alumina feeder through processings of pigtailing. Au wire bonding, epoxing, SMA connecting, sealing. The electrical and optical characteristics were measured after packaging. The electrical properties of S$_{21}$ and S$_{11}$ were obtained as 9.8 GHz at -3 dB and -8.9dB at 14.4GHz, respectively. Optical waveguide prepared met requirements for a single mode at a 1550nm wavelength range. Insertion loss was 4.3dB at room temperature after packaging, and was varied 4.3~6.4dB at various temperatures, 5~45$^{\circ}C$. E-O bandwidth measurement showed 3dB optical response at 7.8GHz, which means that it is applicable for 10Gbps optical communicationon

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Development of 5Gbps Ti:LiNbO$_3$ Mach-Zehnder Interferometric Optical Modulator for High-speed Optical Communications (초고속 광통신용 5Gbps 급 Ti:LiNbO$_3$ Mach-Zehnder interferometric 광변조기 개발)

  • 김성구;윤형도;윤대원;유용택
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1997.11a
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    • pp.477-479
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    • 1997
  • The preparation of mach-zehnder inteferometric optical modulator and the properties of electrode and modulation bandwidth for high speed optical communications were described. The results of fabricated optical modulator was that optical 3-dB bandwidth 4.7GHz, driving voltage 6V and fiber-waveguide-fiber insertion loss 4.5dB for TM mode respectively.

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New Wilkinson Power Divider Using Lumped Elements (집중소자를 이용한 새로운 윌킨슨 전력 분배기)

  • Cho, Seung-Hyun;Park, Chan-Hyeong;Chung, In-Young;Jeong, Jin-Ho
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.46 no.6
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    • pp.128-134
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    • 2009
  • In this paper, we propose a new lumped Wilkinson power divider which is designed to have lower quality-factors in the impedance transformation. Therefore, it can provide wider bandwidth than the conventional one. Moreover, the proposed power divider consists of fewer number of elements so that the circuit size can be further reduced. Simulation results show that the proposed lumped power divider allows a 50% wider bandwidth in the return loss and isolation performance. The conventional and new Wilkinson power was designed and fabricated based on the derived equations at 2.0 GHz. In the measurement, the proposed divider achieved a good performance with an input return loss ($S_{11}$) of -23.0 dB, an isolation ($S_{23}$) of -29.0 dB and an insertion loss ($S_{21}$) of -3.12 dB at the design frequency with wider bandwidth than the conventional one.

Analysis and assessment of the gain of optically pumped surface-normal optical amplifiers (광여기 면형 광증폭기의 이득해석 및 제작)

  • 김운하;정기태;조용환
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.25 no.1B
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    • pp.8-14
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    • 2000
  • This paper analyzes and accesses the gain of optically pumped surface-normal MQW optical amplifiers. The proposed amplifiers have the advantage of polarization independence, high coupling efficiency to and from optical fibers, and flexibility of operating wavelength. We analyzed the gain characteristics of 100 - 200-period MQWs and verified the dependence of a strained lattice and selective doping. Theoretical analysis of such MQWs showsa single-pass gain of 3 dB with broad operation bandwidth. A single-pass gain of 2.6 dB is obtained experimentally in an InGaAs/InGaAlAs MQW amplifier, which is compared with calculations. The use of Fabry-Perot interferometer (FPI) structure in an optical amplifier is a useful way to increase the gain, but causes a problem of narrow operation bandwidth when the single-pass gain is low. Therefore, a single-pass gain above 2to 3 dB is a prerequisite to achieve both a high gain and moderate operation bandwidth in FPI-structured opticalamplifiers. We have designed an FPI-structured surface-normal optical amplifier both with a high gain of broad operation bandwidth of 4.6mm, when a single-pass gain is 3 dB.

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A Wideband Circularly Polarized Pinwheel-Shaped Planar Monopole Antenna for Wireless Applications

  • Lee, Wang-Sang;Oh, Kyoung-Sub;Yu, Jong-Won
    • Journal of electromagnetic engineering and science
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    • v.12 no.2
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    • pp.155-160
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    • 2012
  • A wideband circularly polarized pinwheel-shaped planar monopole antenna fed by a wideband feeding network is presented in this paper. The proposed antenna is formed by four wideband planar monopole antenna elements with aquadruple feeding network in order to improve the performance of circular polarization. Additionally, the antenna, which is introduced here, has a high gain in the z axis direction because of its folded antenna structure. The attractive characteristics of the proposed antenna are the wide impedance bandwidth of 87.3 % (1 GHz to 2.55 GHz), the 3 dB axial ratio (AR) bandwidth of 92.3 % (1.05 GHz to 2.85 GHz), and the maximum gain within the 3 dB AR bandwidth is about 8.24 dBic.

Design of a Low-Profile, High-Gain Fabry-Perot Cavity Antenna for Ku-Band Applications

  • Nguyen, Truong Khang;Park, Ikmo
    • Journal of electromagnetic engineering and science
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    • v.14 no.3
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    • pp.306-313
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    • 2014
  • A Fabry-Perot resonator cavity antenna for Ku-band application is presented in this paper. The Fabry-Perot cavity is formed by a ground plane and a frequency selective surface (FSS) made of a circular hole array. The cavity resonance is excited by a single-feed microstrip patch located inside the cavity. The measured results show that the proposed antenna has an impedance bandwidth of approximately 13% ($VSWR{\leq}2$) and a 3-dB gain bandwidth of approximately 7%. The antenna produces a maximum gain of 18.5 dBi and good radiation patterns over the entire 3-dB gain bandwidth. The antenna's very thin profile, high directivity, and single excitation feed make it promising for use in wireless and satellite communication applications in a Ku-band frequency.

The Research of Single Fed Broadband Planar Array Antenna with Modified Stacked-Structure using Circular Polarization (변형된 적층구조를 갖는 단일급전방식의 광대역 평판형 배열안테나 연구)

  • 정영배;이영환;문정익;박성욱;하재권
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.12 no.6
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    • pp.919-930
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    • 2001
  • This paper presents a wideband technique of impedance and axial-ratio bandwidth which uses the stacked planar array structure through optimum design of sub-polarization generating sections and parasitic patch. So, the effect of the dual-resonance characteristic can contribute to the bandwidth expansion of single fed planar array antenna using circular polarization which doesn\`t hire previous bandwidth expansion technique. The antenna can be used as a dual-band antenna by adjusting the resonance frequencies as well, and then the antenna is designed and fabricated in the frequency band of domestic satellite-TV service. This antenna has the performance of 9.7 % impedance bandwidth and 24 dBi of antenna gain. And it has also 2.8 % and 1.4 % of 3 dB Axial-ratio bandwidth at 11.4 GHz and 11.8 GHz respectively.

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Dual-Polarized Tx/Rx Antenna for UHF RFID Reader (UHF RFID 리더기용 송수신겸용 이중편파 안테나)

  • Kang, Chae-Woon;Yun, Gi-Ho
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
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    • 2005.11a
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    • pp.231-234
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    • 2005
  • In this paper, Dual-polarized Tx/Rx antenna for RFID reader is designed and fabricated to apply to RFID reader. Each feeding network of Tx/Rx is designed to improve the port-isolation and cross-polarization, and sequential rotation feeding scheme has been applied to increase of axial ratio bandwidth. Measured results show that 2.35dBi of antenna gain in 900MHz$\sim$928MHz, 150MHz of 3dB axial ratio bandwidth, -38dB$\sim$-40dB of port-isolation, and -30dB$\sim$-40dB of cross-polarization.

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Disk Sector Antenna fed by CPW for UWB Communications (UWB 통신용 CPW 급전 디스크 섹터 안테나)

  • Lim, Jung-Hyun;Lee, Min-Soo;Yang, Doo-Yeong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.10 no.2
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    • pp.303-312
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    • 2009
  • In this paper, we design and fabricate a disk sector antenna fed by CPW fur UWB communications. Also, we insert a rectangular slit on the arc-edge of the disk sector antenna. Then, the antenna has the directivity of E-면. In order to design the antenna, the input impedance is matched with the feed line of $50{\Omega}$ as varying the physical antenna parameters, which are the radius, the flare angle of disk sector, the length of ground, and the length of ground comer near by feed tine. Dimension of the antenna designed for UWB communication is $72mm{\times}26mm$ and bandwidth through computer simulation is $3{\sim}13GHz$. From the measured results, the bandwidth is $1.98{\sim}11GHz$. Return loss and gain of the fabricated antenna are -50.38dB, 1.34dBi at 3.5GHz, -12.27dB, 3.35dBi at 5.5GHz, -23.2dB, 3.8dBi at 8GHz and -16.17dB, 5.2dBi at 10GHz, respectively.