PROJECT TITLE :

Compact Dual Circularly Polarized Primary Feeds for Symmetric Parabolic Reflector Antennas

ABSTRACT:

Four-arm Archimedean spiral antennas, capable of generating both senses of circular polarization with broadside radiation patterns, are investigated as a primary feed in symmetrical parabolic reflector antennas with circular rims. Unidirectional, center-fed, and compact spiral antennas are studied, backed by a planar reflector as a ground plane. Both right- and left-handed circularly polarized fields with broadside radiation patterns, in line with the first and third modes of the spiral, are realized by confining the radiation zone to less than a 3-wavelength circumference. The proposed feed exhibits glorious pattern symmetry and axial ratios well below zero.five dB at the boresight direction for both senses of polarization. During this letter, the performance of the proposed spiral antenna is absolutely addressed as primary feeds in symmetrical parabolic reflector antennas. Different antenna parameters like gain, cross polarization, and efficiency are studied for paraboloids, having completely different focal-length-to-diameter ratios, for both senses of circular polarization. Efficiencies of seventy% and higher are obtained over a frequency band of 2.5-five.0 GHz.