Vehicular Diversity Flat Antenna at 900 MHz

Hiroyuki ARAI  Hideki IWASHITA  Naohisa GOTO  

IEICE TRANSACTIONS on Communications   Vol.E74-B   No.10   pp.3222-3226
Publication Date: 1991/10/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Mobile Communication Antennas)

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A flat diversity antenna, consisting of a disk loaded monopole antenna and four notch antennas composed in the same disk, was proposed as a vehicular antenna to reduce a fading effect of urban mobile telephone. The disk loaded monopole antenna is fed by a center probe and has four matching posts to realize the same pattern as that of a monopole antenna over a wide frequency range. This paper presents a new feed circuit for the flat diversity antenna, and measurement results of its input characteristics and radiation pattern when it is mounted on a vehicle. To verify the diversity effect of this antenna, we measured urban propagation characteristics at 900MHz, and compared the results with those of a space diversity antenna. We obtained almost the same characteristics with the flat diversity antenna as with the space diversity antenna.