The Bandwidth and the Gain of Radial Line Slot Antennas with Uniform Slot Density

Jun-ichi TAKADA  Makoto ANDO  Naohisa GOTO  

IEICE TRANSACTIONS (1976-1990)   Vol.E73   No.8   pp.1372-1377
Publication Date: 1990/08/25
Online ISSN: 
Print ISSN: 0000-0000
Type of Manuscript: PAPER
Category: Antennas and Propagation

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A Circularly-Polarized Radial Line Slot Antenna (CP-RLSA) is a high gain planar antenna for DBS reception. From the practical point of view, it is necessary to overlook the performance of RLSA as a function of various design parameters. This paper presents the general design of CP-RLSA with uniform slot density and predicts the bandwidth and the gain of RLSA by array antenna analysis. In the calculation, the slot coupling is evaluated by full wave analysis and the effects of all the design parameters are taken into account. The long line effect reduces the bandwidth of RLSA monotonously with the antenna diameter. The bandwidth is limited by slot resonance as well and the overall bandwidth is less dependent of the diameter. 3dB bandwidth of 650 MHz is predicted for antenna diameter of 600 mm, for example. Among various design parameters, permittivity of slow wave structure affects the bandwidth and gain considerably; εγ1.41.8 is preferable. On the other hand, the height of waveguide and the slot pair angular spacing have little influence, though lower waveguide and smaller spacing are advantageous for a stable rotational symmetry of inner field.