On the functioning of folded dipole antennas on conducting masts

McNamara, D.A.; Botha, Louis

doi:10.1109/25.260774

Cited by 8 publications

(2 citation statements)

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“…Numerical results obtained for the input impedance of various lengths of the dipole in free space have shown agreement with reference (McNamara and Botha, 1993) in the forward gain but not for the Zi.. For 2h=0.46m, wire radius ~0 . 0 0 1 r n and width 6=0.003m (see Figure 2) at the frequency of 300MHz the Zi, was found to be equal to 301.2+j64.350 while at 291MHz it is 280.2-j2.70 which means that is very nearly resonant.…”

Section: Numerical Resultssupporting

confidence: 62%

On the Design of a Hybrid-Chebyshev Collinear Folded Dipole Antenna Array

1998

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The arrangement of a Mast-mounted folded dipole antenna array with comer reflectors is considered. The method of moments (MOM) in a wire grid model is used and a suitable optimization procedure is applied.Due to the constraints for high power gain and low SLL the array is designed as a simple broadside Chebyshev one. The presence of 120" comer reflectors change the pattern and makes the array to be a HybridChebyshev one with approximately the same SLL. The distance of the array from the comer of the reflector is critical for the HPBW. Two different types of antennas with 60" and 120" HPBW in the horizontal plane for possible mobile applications are studied.The whole design work is given in a general form, usehl for VHF and UHF communication applications. To ensure the accuracy, two different wire grids for each model are used. In the examples several interesting cases will be analytically presented.

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Section: Numerical Resultssupporting

confidence: 62%

On the Design of a Hybrid-Chebyshev Collinear Folded Dipole Antenna Array

1998

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“…Previous investigations of the effects of antenna masts have been restricted to the horizontal pattem distortions of a single folded dipole on an ideally conducting mast (3); the influence of mounting structures and of the dielectric properties of the roof on the pattem has, to our knowledge, not been treated previously. In this paper, we analyze the amount of distortion introduced by masts of various thickness on a typical array antenna that is widely used as a base station antenna for mobile communications networks.…”

Section: Introductionmentioning

confidence: 98%

Pattern distortion of mobile radio base station antennas by antenna masts and roofs

Molisch

Fuhl

Bonek

1995

25th European Microwave Conference, 1995

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We analyze the influence of antennamasts, mounting structures, and roofs on the radiation pattem of base station antennas tor mobile communications. The distortions in the horzontal radiation pattem of omniantennas caused by the mast can be up to 1 OdB, but the mast conductivity has only minor effects. The antenna mast also leads to a reduction in the sidelobe attenuation of the vertical radiation pattem of an array antenna. Mounting structures (horizontal metallic bars) have only a very small influence on the pattem. Finally, the rooftops on which the antennas are mounted can also lead to very strong (>10dB) distortions of the radiation pattenm. These effects must be considered in the cell planning for mobile radio communications networks.

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