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Susumu HORIGUCHI Takayuki ISHIZONE Yasuto MUSHIAKE
The method of improvement on the polarization property of a turnstile spherical array antenna is proposed and its numerical results are discussed. It is found that the spherical array becomes capable of scanning its beam up to large angle with circular polarization through the improvement.
Susumu HORIGUCHI Takayuki ISHIZONE Yasuto MUSHIAKE
Effects of the element radiation pattern on characteristics of the spherical array antenna composed of turnstile elements is discussed. It is found by numerical calculations that scanning characteristics of the directivity and the axial ratio do not so much depend on element radiation patterns.
Masanobu HIROSE Takayuki ISHIZONE Koji KOMIYAMA
We have shown that a photonic sensor can be used as an electric-field probe for planar near-field measurements of X-band antennas. Because an antenna on the photonic sensor is small (about 0.1 λ) compared to the wavelength, the photonic sensor can directly measure the amplitude and the phase of the electric field close (about 0.3 λ) to the apertures of antennas without disturbing the electric field to be measured. Therefore we can obtain the antenna pattern by transforming the measured electric field without probe compensation. To verify the merits of the photonic sensor, we have evaluated the antenna patterns of a standard gain horn antenna and a microstrip array antenna at 9.41 GHz. Comparing the results obtained using the photonic sensor with those obtained using the conventional open-ended waveguide probe and other methods, we have shown that the antenna patterns agree with each other within 1 dB over wide ranges of directivity.
Yuanfeng SHE Masanobu HIROSE Yuto KATO Takayuki ISHIZONE Satoru KUROKAWA Shinya IWASAWA Sintaro ARATA
This article proposes a simply structured transverse slot linear array antenna with a low cross-polarization in X band on a quasi-TEM (transverse electromagnetic) mode waveguide. The fabrication technology of this antenna is very simple and suitable for mass production. A center fed linear slot array has been designed and measured. The quasi-TEM wave is propagating in the conventional waveguide with dielectrics at sidewalls. The simulation and the measurement results show that the baffle plates enhance the gain and reduce the beamwidth effectively. The uncertainties of the electric properties of the dielectric and fabrication errors are also discussed.