Spherical dipole antenna using optical/electrical converter

Self Cite

SUMMARYSite attenuation has been evaluated by means of a half-wave dipole antenna. Since this antenna type requires a size on the order of a half wavelength, it is not suitable for evaluation of small anechoic chambers. In this paper, a method of evaluation of small anechoic chambers using a spherical dipole antenna with a diameter of 15 cm is discussed. First, the spherical dipole antenna is modeled by wire grids and the site attenuation and antenna factor are derived. It is found that in the range of 30 MHz through 1000 MHz the discrepancy between the analytical values and the measured values of the site attenuation is less than ±4 dB, while that of the antenna factor is less than ±2 dB. Next, the site attenuation taking account of the reflection characteristics of the anechoic chamber is analyzed by the ray tracing method. As parameters, the antenna factor and the radiation pattern derived from the wire grid model are used for the antenna characteristics, and the reflection coefficient derived from the multilayer plane approximation method is used for the reflection characteristics of the absorber. It is found that the discrepancy between the analytical values and the measured values for the site attenuation distribution at a frequency of 600 MHz is less than ±3 dB, and the ray tracing method is found useful for the analysis of the site attenuation distribution using a spherical dipole antenna. Further, when the new approach is applied to a small anechoic chamber in which absorbers with different characteristics are included, the present method is found effective for evaluation of the areas with good properties and of the effect of the absorbers.

“…3 is close to the results presented in Ref. 6. Also, the gain obtained is close to that of the short dipole.…”

Section: Analysis Model For a Spherical Dipole Antennasupporting

confidence: 93%

Section: Analysis Model For a Spherical Dipole Antennamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Evaluation method of small anechoic chamber by site attenuation distribution using spherical dipole antenna

Kitani

Kuwabara

Kawabata

et al. 2005

Self Cite

“…Presently, there are numerous sensors for electric field measurement. Examples are FET sensors [1] and sensors with E/O converters [2]. The electric field sensors using an optical modulator are advantageous because (1) the sensor parts except for the sensor rod are nonmetallic and do not disturb the electric field under measurement, (2) it has a wide-band frequency characteristic because the modulator performs in the wide frequency band, and (3) it is suitable for long-term measurement and for measurement near electric equipment because it is compact and does not need a battery.…”

Section: Introductionmentioning

confidence: 99%

Optical bias angle control method for electric field sensor using Mach-Zehnder interferometer

Kobayashi

Tajima

Kuwabara

et al. 2000

Self Cite

An electric field sensor using a Mach‐Zehnder interferometer can be made compact, used for wide‐band applications, and does not disturb the surrounding electromagnetic field. Because of these merits, its application to EMC measurement is promising. However, because it is not clear how to adjust the operating point (optical bias angle) of the optical modulator used for the electric field sensor, its dynamic range is limited. This paper proposes a method to adjust the operating point by applying force to a point on the optical crystal substrate used for the optical modulator. First, the relationship between the applied force and optical bias angle is theoretically analyzed, taking into account the change in waveguide length and change in the refractive index when load is applied. Then, it is shown that the change in the waveguide length is more dominating than the change in the refractive index. An electric field sensor was actually fabricated to show that the optical bias angle can be adjusted as theoretically predicted and that its temperature dependence is comparable to that of a conventional electric field sensor. © 2000 Scripta Technica, Electron Comm Jpn Pt 1, 83(8): 53‐61, 2000

Research and development on EMC/EMI measurements and technologies in Japan

Takagi¹

1999

SUMMARYThis paper describes five items in the field of measurement of electromagnetic waves and of electromagnetic interference (EMI) as related to electromagnetic compatibility (EMC), namely: interference measurement devices and the problem of site attenuation, to which Japan has contributed significantly, and the measurement of electromagnetic fields, electrostatic discharges (ESD), and EMI, and the immunity of communication equipment, to which Japan should be able to contribute substantially. With regard to electromagnetic field measurement, the electric field sensor using a MachZehnder interferometer, a spherical dipole antenna, and a broadband standard dipole antenna, developed in this country for practical use, are described with regard to their structures and characteristics. It is noted that there are several unresolved problems related to electrostatic discharge, due to its anomalous nature, and that in particular the phenomenon of indirect ESD is important for the EMI problem of electronic equipment. The topics of interference measurement devices and site attenuation have seen significant international standardization, and Japan has been in a leading position in these areas. The methods for the measurement of EMI of communication equipment and the question of immunity urgently need to be resolved and require standardization in the very near future. Japan is also a world leader in these areas and strongly promoting research on them. © 1999 Scripta Technica, Electron Comm Jpn Pt 1, 82(11): 8392, 1999