• Title/Summary/Keyword: UHF Band

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Effect Analysis of Surface-Icing on the UHF-band Antenna for Space Launch Vehicle (우주발사체용 UHF-대역 안테나의 표면결빙에 의한 영향분석)

  • Hwang, Soosul;Oh, Changyul;Ma, Keunsu
    • Journal of Satellite, Information and Communications
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    • v.9 no.3
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    • pp.104-108
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    • 2014
  • This paper represents the effect analysis results of surface-Icing on the UHF-band antenna for Space Launch Vehicle. In order to obtain structural model of the surface-icing, Relative Permittivity of ice at $-180^{\circ}C$ was extracted. Using this surface-Icing model, UHF-band antenna simulation and comparative analysis about the antenna parameters such as resonance frequency, reflection loss and radiation pattern were performed for each case of with or without surface-icing. Simulation results show that resonance frequency is shifted out of operation frequency due to the additional ice permittivity. This resonance frequency changes cause severe affect to the antenna performance and its radiation pattern.

A Cancellation Technique of TX Leakage Signal for Emhanced Readability in UHF-band RFID Readers (UHF대역 RFID Reader에서 인식률 향상을 위한 송신누설신호 상쇄기술)

  • Noh, Eui-Ho;Lee, Jong-Hyuk;Kim, Nam-Yoon;Kim, Chang-Woo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.36 no.5A
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    • pp.543-550
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    • 2011
  • In order to improve readability, a leakage-signal canceller has been proposed in UHF-band RFID readers. The proposed canceller is composed of two blocks: an environment monitoring block for detection of Tx and RX power levels and a leakage cancellation block. The leakage canceller consists of directional-couplers, digital attenuators and phase shifters based on the feed-forward scheme. The leakage canceller is located between antenna and reader. An improved experimental characterization of the scheme is presented with results from the reader operating in the Korean RFID frequency band, conforming the validity of the approach with more than 29 dB of leakage cancellation.

Performance Verification of the Gas Insulated Switchgear using UHF Partial Discharge Diagnosis Method (UHF 부분방전 진단법에 의한 가스절연 개폐장치의 성능검증)

  • Kim, J.B.;Jung, J.R.;Kim, M.S.;Song, W.P.;Kim, M.H.;Ko, H.S.;Choi, I.H.
    • Proceedings of the KIEE Conference
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    • 2004.05b
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    • pp.132-135
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    • 2004
  • In generally, compared with VHF band, electromagnetic waves of UHF band have a low influence for external noise. We can detect the real abnormality with several pC in GIS using UHF method. Recently, it has applied to use the external UHF sensor attached on spacer to GIS of existing substation. In this paper, we firstly described the technique of the partial discharge measurement using frequency analysis and phase analysis in UHF band. Secondly, we presented the results of sensitivity, the relationship of dBm-pC and diagnosis of the reason of PD source by phase analysis. And then, we report the diagnosis result of partial discharge on 800kV GIS in domestic substation. rge diagnosis of GIS.

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Modeling of Propagation Interference and Channel Application Solution Suggestion In the UHF Band RFID Propagation Path (UHF 대역 RFID 전파경로에서의 전파간섭 모델링 및 채널 운용 방안 제안)

  • Moon, Young-Joo;Yeo, Seon-Mi;Jeon, Bu-Won;Roh, Hyoung-Hwan;Joung, Myoung-Sub;Oh, Ha-Ryoung;Seong, Yeong-Rak;Park, Jun-Seok
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.57 no.11
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    • pp.2047-2053
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    • 2008
  • Auto-ID industries and their services have been improved since decades ago, and radio frequency identification (RFID) has been contributing in many applications. Product management can be the foremost example. In our industrial experiences, RFID in ultra high frequency (UHF) band provides much longer interrogation ranges than that of 13.56MHz; many more applications exist thereby. There should be several interesting and useful ideas on UHF RFID; however, those ideas can be limited due to the inevitable environmental circumstances that restrict the interrogation range in shorten value. This paper discusses the propagation interference among different types of readers (e.g, mobile RFID readers in stationary reader zone) in dense-reader environment. In most cases, UHF RFIDs in Korea will be dependent on the UHF mobile RFIDs. In this sense, the UHF mobile users accidently move into the stationary reader's interrogation zone. This is serious problem. In this paper, we analyze propagation loss and propose the effective channel allocation scheme that can contribute developing less-invasive UHF RFID networks. The simulation and practical measurement process using the commercial CAD tools and measurement equipments are presented.

A Study for the Fault Location of Insulation Defects considering Waveguide Characteristics in GIS (GIS의 도파관 특성을 고려한 절연결함 위치판정에 관한 연구)

  • Lee, Seung-Chul;Jung, Seung-Yong;Lee, Jae-Ho;Koo, Ja-Yoon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.57 no.2
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    • pp.252-255
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    • 2008
  • A study for discharge pattern analysis partial and fault location by use of UHF sensors in GIS. However, in the latter case, the results considered the velocity of EM waves modified by the waveguide characteristics of GIS bus bar were not reported yet. In this paper, UHF wide band sensor to detect partial discharge signals have been designed and manufactured to get the widest band characteristic by an application of Fat-Dipole UHF antenna and the result that the transmission velocity of EM waves is 2/3 of the light have been got through the consideration of waveguide characteristics. Also, to verify applicability on site of the developed method, self-designed external type UHF sensor have been installed on operating GIS in Korea Midland Power co. and detected location of the fault. Through the fault have been found at the location, the reliability of the developed method have been proved.

UHF & HF RFID Credit Card Size Tag Antenna Designs Using Silver-Ink and Jumper Structure (실버잉크와 점퍼구조를 사용한 신용카드 크기의 UHF & HF RFID 태그 안테나)

  • Nam, Sehyun;Chung, Youchung
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.27 no.11
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    • pp.972-977
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    • 2016
  • This paper introduces development process and results of HF & UHF band(13.56 MHz, 920 MHz) tag antennas using a single-side printing method on a PE film. The size of tag antenna is designed in the area of $80mm{\times}50mm$, little bit smaller than a credit card. The UHF tag antenna, $76mm{\times}44mm$, is located at the outside of the card size tag antenna, and the HF tag antenna, $40 mm{\times}42 mm$, is located at the center of the UHF tag antenna. The UHF and HF tag antennas are designed with consideration of coupling effects. The single-side printing method with a jumper structure without using a via is used to make a loop antenna of HF tag antenna. The reading range of UHF tag antenna is about 6m, and the reading of HF tag antenna is about 5 cm. The designed tag antennas have long enough reading ranges for both bands. The tag is applicable to logistics and authentification.

Design of a compact quasi-Yagi antenna for portable RFID reader (휴대형 RFID 리더용 소형 준-야기 안테나 설계)

  • Lee, Jong-Ig;Yeo, Junho;Baek, Woon-Seok
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.20 no.1
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    • pp.15-21
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    • 2016
  • In this paper, we considered a design method of a compact quasi-Yagi antenna for portable UHF RFID readers. The antenna consists of a dipole driver and a reflector printed on a dielectric substrate, and it is fed by a microstrip line. In order to reduce the antenna size, the dipole and reflector are bent and the balun between the feeding microstrip line and coplanar strip (CPS) line is integrated within the CPS line. The effects of the geometrical parameters of the proposed antenna on the antenna performance are examined, and the parameters are adjusted to be suitable for the operation in UHF RFID band (902-928 MHz). The size of the fabricated antenna is $70mm{\times}75mm$, and the experiment results reveal a frequency band of 892-942 MHz for a voltage standing wave ratio < 2, a gain > 3.5 dBi, and a front-to-back ratio > 6.6 dB over the frequency band for UHF RFID.

V/UHF-Band Broadband 2-Way Power Divider (V/UHF-대역 광대역 2분기 전력 분배기)

  • Park, Yeo-Il;Ko, Jin-Hyun;Park, Young-Joo;Park, Dong-Chul
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.18 no.4 s.119
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    • pp.416-422
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    • 2007
  • In this paper, a broadband 2-way power divider which can be used from 20 MHz to 500 MHz in the V/UHF band is designed using transmission-line transformer and ferrite toroid. A 2:1 impedance transformer instead of the conventional 4:1 impedance transformer is realized and this 2:1 transformer is connected with the conventional bridge-type 2-way divider to form a 2-way power divider. Insertion loss of about 3.5 dB, isolation of less than -10 dB, and return loss of less than -10 dB in most band of interest are measured.

Design of a V/UHF-Band Broadband 4-Way Power Divider (V/UHF-대역 광대역 4분기 전력 분배기 설계)

  • Park, Yeo-Il;Ko, Jin-Hyun;Ha, Jae-Kwon;Park, Young-Joo;Park, Dong-Chul
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.18 no.8
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    • pp.904-912
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    • 2007
  • In this paper, a broadband 4-way power divider which can be used from 20 MHz to 500 MHz in the V/UHF band is designed using transmission-line transformer and ferrite toroid. A 4:1 impedance transformer is realized and this 4:1 transformer is connected with bridge-type 2-way dividers to form a 4-way rower divider, Insertion loss of about 6.8dB, isolation of less than -20dB, and return loss of less than -15dB in most band of interest are measured.

Study on the UHF-band Variable Attenuator Using the 3-dB Coupler (UHF대역 3-dB 커플러(Coupler)를 이용한 가변 감쇄기(Attenuator)에 대한 연구)

  • 박경태
    • Journal of the Institute of Convergence Signal Processing
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    • v.2 no.2
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    • pp.68-74
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    • 2001
  • A design and implementation method for the UHF-band(800MHz) variable attenuator using the 3dB coupler is proposed. The 90 degree, 3-dB Coupler is used for the variable attenuator. The principal theory for the 3-dB coupler is introduced. The 3-dB Coupler is designed by the mathematical analysis and a computer simulation tool. A PIN diode is used for the variable resistor at UHF-band. The variable attenuator using the 3-dB coupler and the PIN diode is designed and implemented. The measured results for the variable attenuator by a network analyzer show that the insertion loss is below -l0dB, and the continuous variable attenuation range is about 10dB.

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