• Title/Summary/Keyword: 3 dB bandwidth

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Wide Bandwidth Circularly Polarized Aperture Coupled Microstrip Antenna using Cross-slot (십자 슬롯을 이용한 광대역 원형편파 적층 개구결합 마이크로스트립 안테나)

  • 양태식;이범선
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.11 no.5
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    • pp.748-754
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    • 2000
  • A novel single feed wide band CP stacked microstrip antenna using crossed slots has been designed, fabricated and measured. For the single rediating element the designed 10dB return loss bandwidth is 34.5%99.45~13.54 GHz), 3dB axial ratio bandwidth is 18.7%(11.17~13.39GHz), and 6 dB gain bandwidth is 29%(10.21~13.64GHz). For the 2$\times$2 array designed using a sequential rotation method, the 10dB return loss bandwidth is 35.9%(9.69~13.94GHz), 3dB axial ratio bandwidth is 34.6GHz (9.93~14.03GHz), and 6dB gain bandwidth is 27.4%(10.35~13.6GHz). For the fabricated 8$\times$8 array antenna, the 10dB return loss bandwidth is 27.3%(10.17~13.41GHz), 3dB axial ratio bandwidth is 27.9GHz(10.1~13.4GHz), and the radiation pattern is good agreement with theory. This antenna can be used for broadband applications for communications or broadcasting in Ku band.

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Asymmetric and symmetric modified bow-tie slotted circular patch antennas for circular polarization

  • Darimireddy, Naresh K.;Reddy, R. Ramana;Prasad, A. Mallikarjuna
    • ETRI Journal
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    • v.40 no.5
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    • pp.561-569
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    • 2018
  • Modern communication systems employ wideband antennas with circular polarization (CP) radiation. In this work, asymmetric modified bow-tie (ABT) and symmetric modified bow-tie (SBT) slotted circularly polarized single-point probe-fed circular patch antennas with dimensions of $40mm{\times}40mm$ for wideband applications are proposed. A 10 dB RL bandwidth of 350 MHz with CP, 3 dB axial ratio (AR) bandwidth of 100 MHz, peak gain of 4.9 dBic, and 10 dB RL bandwidth of 530 MHz with CP, 3 dB AR bandwidth of 140 MHz, peak gain of 5 dBic are obtained for ABT and SBT slotted circular patch antennas, respectively. The proposed SBT slotted patch is scaled up and down to $50mm{\times}50mm$ and $30mm{\times}30mm$, respectively. The proposed scaled-up version offers 10 dB RL and 3 dB AR bandwidths of 340 MHz and 80 MHz, with a peak gain of 5 dBic. The scaled-down version offers 10 dB RL and 3 dB AR bandwidths of 710 MHz and 180 MHz, with a peak gain of 5.25 dBic. These prototypes are suitable to work in IEEE 802.11a WLAN, ISM, and IEEE 802.11ac applications. The measured and simulated results are then discussed and compared.

Fixed Biased 4-D Multiple-Subcarrier Signal for Average Power Reduction in Optical Wireless Communication (Fixed bias를 가지는 4-D Multiple-Subcarrier 신호를 이용한 Optical Wireless 통신의 평균 전력 절감에 관한 연구)

  • 김해근
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.40 no.10
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    • pp.103-109
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    • 2003
  • We have proposed the 4-Dimensional Multiple-Subcarrier Modulation with fixed bias in Optical Wireless Communications. Here, the 4-D signal vectors are derived from the optimization technique of signal waveforms maximizing the minimum distance between signal points in an n-dimensional Euclidean sphere. The resulting vectors are used in generating the output amplitude of impulse generator in a Multiple-Subcarrier Modulation scheme. We have achieved that the normalized power requirement of the proposed system is maximum 3 dB and 3.3 dB smaller than those of normal QPSK, Reserved Subcarrier, and Minimum Power scheme, respectively. Also, in the range of 1.125 ∼ 1.25 of the normalized bandwidth, the proposed system has maximum 3 dB, 2 ∼ 4 dB, 0 ∼ 3 dB smaller bandwidth requirement compare to normal QPSK, Res. Subcarrier, Min. Power schemes, respectively.

A Study of The Eyequency Response Improvement of TO-can Package for SFF/SFP Optical Transceiver (SFF/SFP 장 송수신기용 TO-can 패키지 주파수 응답 향상 연구)

  • Lee Sang-Hoon;Jung Hyun-Do;Koo Bon-Jo;Han Sang-Kook
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.1A
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    • pp.107-112
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    • 2004
  • We propose the optimum TO-can package design in SFF/SFP optical transceiver modules to improve 3dB-bandwidth. The frequency response of TO-38 package is measured and compared to simulation where the 3dB-bandwidth was 3.5GHz. For a higher operating bandwidth (>15GHz), the new optimized physical geometries of TO-can package such as bonding-wire, lead and material was suggested. The optimal result of simulation shows that TO-can package can be used at a higher bit rate optical module of 10Gbps.

A Varactor-Tuned RF Tunable Bandpass Filter with Constant Bandwidth

  • Kim, Byung-Wook;Yun, Du-Il
    • Journal of electromagnetic engineering and science
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    • v.1 no.2
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    • pp.166-172
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    • 2001
  • A novel RF tunable bandpass filter structure using dielectric resonators and varactor diodes is considered for the optimization to achieve constant bandwidth with minimum passband insertion loss. The coupling between resonators is realized by coupling windows and series lumped L, C elements are used to realize the input/output stage couplings. A 5 poles, 0.01 dB ripple Chebyshev type filter tuned from 800 MHz~900 MHz is designed and presented in this paper. The passband bandwidth for the design is 10 MHz (fractional bandwidth = 1.2 %). Experimental results show that the 3 dB passband bandwidth variation is 12.04 MHz~12.16 MHz (less than 1 %) and passband insertion loss is 15 dB~7 dB depending on the tuning voltages.

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Bandwidth Enhancement of Circularly Polarized Dielectric Resonator Antenna

  • Sun, Ru-Ying
    • ETRI Journal
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    • v.37 no.1
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    • pp.26-31
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    • 2015
  • Axial-ratio (AR) bandwidth enhancement is achieved for a circularly polarized (CP) cylindrical dielectric resonator antenna (DRA) using a wideband hybrid coupler (WHC) combined with dual probe feed. The presented WHC, comprised of a Wilkinson power divider and a wideband $90^{\circ}$ shifter, delivers good characteristics in terms of 3 dB power splitting and consistent $90^{\circ}$ (${\pm}5^{\circ}$) phase shifting over a wide bandwidth. In turn, the proposed CP DRA, for the employment of the WHC, in place of conventional designs, provides a significant enhancement on AR bandwidth and impedance matching. The antenna prototype with the WHC exhibits a 3 dB AR bandwidth of 48.66%, an impedance bandwidth of 52.5% for voltage standing wave ratio (VSWR) ${\leq}2$, and a bandwidth of 44.66% for a gain of no less than 3 dBi. Experiments demonstrate that the proposed WHC is suitable for broadband CP DRA design.

Circular Polarization Circular Microstrip Antenna using the Perturbation Effect (Perturbation 효과를 이용한 원편파 원형 마이크로스트립 안테나)

  • Ryu, Mi-Ra;Woo, Jong-Myung;Hur, Jung
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
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    • 2005.11a
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    • pp.293-296
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    • 2005
  • This paper presents the design of linear and circular polarization baseball- shaped circular microstrip antenna (BCMA) with 3-dimensional structure using perturbation effect to reduce its size, which runs at 1.575GHz frequency bandwidth. As a result, the size of linear polarized antenna could be reduced up to 23.7% in patch diameter and 41.8% in its area. Linear polarized antenna has -26.04dB of return loss, 69MHz(4.38%) of -l0dB bandwidth, 4.51dBd of gain, and its -3dB beamwidth are 99$^{\circ}$ in E-plane, 83$^{\circ}$ in H-plane. Circular polarized antenna has -17.43dB of return loss, 113.7MHz(7.2%) of -l0dB bandwidth, 2dBd of gain, 2dB of axial ratio and its -3dB beamwidth are 87$^{\circ}$, 86$^{\circ}$ x-axis polarized, 80$^{\circ}$, 84$^{\circ}$ y-axis polarized. It has 82mm of diameter, which is 28.5% of linear polarized CMPA. Therefore, in this paper we verified that baseball-shaped 3-dimensional structure of circular microstrip patch antenna applied with perturbation effect is appropriate for miniaturization.

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Gain bandwidth characteristics of erbium-doped Fiber amplifiers for long-haul transmissions (에르븀 첨가 광섬유 증폭기의 장거리 전송에 따른 이득 평탄화 특성)

  • 정희상;이동한;정윤철;안성준;조흥근
    • Korean Journal of Optics and Photonics
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    • v.9 no.3
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    • pp.181-185
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    • 1998
  • Gain characteristic of concatenated erbium-doped fiber amplifiers(EDFA) are studied with a recirculating EDFA loop. For a non-flat gain EDFA, the 3 dB gain bandwidth was reduced to 6 nm after the 20th EDFA. However, for an optimized gain flattened EDFA, in a simple configuration, the 5 dB gain bandwidth was found to be 9nm, even after the 100th EDFA, corresponding to 8000km transmission. This results suggest that the simple optimized flat gain amplifier could be a good candidate for ultra-long distance wavelength division multiplexed transmissions.

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Bandwidth Improvement of Circularly Polarized Microstrip Antenna for an UHF RFID Portable Reader (휴대용 UHF RFID 리더기용 원편파 마이크로스트립 안테나의 대역폭 개선)

  • Kim, Sang-Gi;Choi, Ik-Guen
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.19 no.4
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    • pp.404-410
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    • 2008
  • In this paper, circular polarized microstrip antenna with a conducted hollow cylinder-typed via around the coaxial probe is proposed to enhance the bandwidth of an RFID portable reader microstrip antenna. An antenna of thickness of 6.4 mm and size of $84{\times}84\;mm$ is manufactured with FR4 substrate and its 10 dB return loss bandwidth is measured to be 92 MHz, which is about three times large than the same size's microstrip antenna without hollow cylindrical via. The measured antenna gain and the axial ratio at each are $0.01{\sim}1.825\;dB$ and $2.3{\sim}8.2\;dB$ within 10 dB return loss bandwidth, respectively.

Electrical Characteristics of 3rd Overtone Mode Energy-trapped High Frequency Filter using PbTiO3 System Ceramics (PbTiO3계 세라믹스를 이용한 3차 진동모드 에너지 트랩형 고주파필터의 전기적 특성)

  • 오동언;류주현;윤현상;박창엽;이수호;김종선;정회승
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.16 no.7
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    • pp.593-598
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    • 2003
  • In this paper, 3rd overtone mode energy-trapped filter using modified PbTiO$_3$ system ceramics was manufactured to apply for intermediate frequency(IF) SMD type fillet with splitted electrode and gap size. To investigate the effects of splitted electrode and gap size on filter characteristics of 3rd overtone mode energy-trapped filter, ceramic wafers were fabricated by etching splitted rectangular electrode size(b$\times$d) of b=0.4, 0.6, 0.8, 1mm, d=0.3, 0.4, 0.5, 0.6mm and gap size(c) c=0.2, 0.3, 0.4, 0.6mm, respectively. And then, SMD type ceramic filter were fabricated with the size of 3.7$\times$3.1$\textrm{mm}^2$. SMD type ceramic filter with the size of b=0.8mm, d=0.4mm and gap(c)=0.4mm, which showed insertion loss of 2.951dB, 3dB bandwidth of 54.7kHz and 20dB stop bandwidth of 129.27kHz, was suitable for IF bandpass filter application.