• Title/Summary/Keyword: EMI Monopole Antenna

Search Result 3, Processing Time 0.023 seconds

Mode-Matching Analysis for Complex Antenna Factors of Circular Top-Hat EMI Monopole Antennas (모드 정합법에 의한 원판 부착형 EMI 모노폴 안테나의 복소 안테나 인자 해석)

  • 정운주;김기채
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.14 no.10
    • /
    • pp.1024-1029
    • /
    • 2003
  • This paper presents the complex antenna factor of a top-hat EMI monopole antenna for measuring time domain electromagnetic fields. The approach is facilitated by adding a artificial parallel ground plane above the monopole antenna. This allows use of cylindrical harmonic field expansions in each of three subregions enclosed by the two ground plane. The results show that the complex antenna factor of the top-hat monopole antenna does not diverge at low frequencies. When compared with a monopole antenna, the top-hat monopole antenna has broadband characteristics. In order to verify the availability of the mode-matching method, the input impedance of the antenna were compared with experiments.

Optimal Design of an Antenna for the Detection of Partial Discharges in Insulation Oil (절연유중 부분방전 검출을 위한 안테나의 최적 설계)

  • Lee, Jung-Yoon;Jo, Hyang-Eun;Park, Dae-Won;Kil, Gyung-Suk;Oh, Jae-Geun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.26 no.4
    • /
    • pp.309-314
    • /
    • 2013
  • This paper dealt with the radiated electromagnetic wave detection of partial discharge (PD) in oil for insulation diagnostics of oil-immersed transformers. Three types of electrode system were fabricated to simulate the insulation defects that could occur in oil-immersed transformers. Frequency components of radiated electromagnetic wave in oil was measured by broadband bi-conical antennas of 300 MHz~2 GHz and a spectrum analyzer of 9 kHz~3 GHz. Frequency component of electromagnetic waves from PD in oil were highly distributed at 500 MHz. From the result, a narrow-band monopole antenna with the center frequency of 500 MHz was fabricated. We could detect PD signal in insulation oil without an influence of external noise by a measurement system which consists of the prototype monopole antenna, a LNA (Low Noise Amplifier), an oscilloscope and a spectrum analyzer.

Investigation of Influences of UWB Antennas on Impulse Radio Channel (임펄스 전파 채널에서의 초광대역 안테나 영향 연구)

  • Park Young-Jin;Song Jong-Hwa;Kim Kwan-Ho
    • Journal of the Institute of Electronics Engineers of Korea TC
    • /
    • v.42 no.12
    • /
    • pp.165-170
    • /
    • 2005
  • In this paper, influences of a ultra wideband (UWB) antenna on impulse channel measurement are investigated in time domain (TD) and frequency domain (FD) as well. Firstly, impulse response of an UWB antenna is obtained and then using the result of impulse response of the UWB antenna, influences of the antenna on impulse radio channel is analyzed. Furthermore, using the impulse response of the UWB anenna, method of impulse radio channel analysis is presented by excluding the effect of the antenna from an impulse radio channel. For verifying the theory, a modified conical monopole antenna is designed for measuring impulse radio channel and its impulse response is obtained. After that, in order to investigate the effects of the UWB antenna on an impulse radio channel, multipath environments are set up in an anechonic chamber and transmission coefficient for each multipath environment is measured with an aid of vector network analyzer. Data measured in frequency domain is transformed into those in time domain by way of signal processing. Measurement shows that such properties of the antenna as dispersion and ringing affect impulse radio channel. Moreover, using the impulse response of the antenna, impulse response of only multipath channel is obtained.