Effect of Automobile Body and Earth on Radiation Patterns of Antennas for FM Radio

Kunitoshi NISHIKAWA  

IEICE TRANSACTIONS (1976-1990)   Vol.E67   No.10   pp.555-562
Publication Date: 1984/10/25
Online ISSN: 
Print ISSN: 0000-0000
Type of Manuscript: PAPER
Category: Antenna and Propagation

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The radiation patterns of wire antennas on an automobile are studied at FM radio frequencies in the presence of the earth. The computational technique is besed on the wire-grid method and the reflection coefficient method. The antennas considered are a vertical monopole and a horizontal dipole mounted on the roof side and the rear window of the body, respectively. It is verified from experimental studies that the computation of the radiation pattern is reasonably accurate. Because of the effect of the body and the earth, in the case of the vertical monopole, a large component of the cross-polarized field and the lobes are generated; and in the case of the horizontal dipole, the direction of the maximum radiation faces nearly to the zenith and the radiation field becomes very weak. The computational technique and the results obtained are useful in the design of the automobile antenna system for an FM radio.