Polarization stability of 4 arm-planar spiral structures

The dependence of the crosspolarization discrimination on the antenna shape and the feeding network is reviewed. The influence of the antenna shape is described by a new characteristic quantity: the polarization stability factor. This quantity is considered for four arm planar archimedean and logarithmic spiral antennas. With these structures high polarization stability can be obtained yielding a high degree of polarization purity with no need for an extremely optimized feeding network.<
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