How can two linearly polarized Yagi antennas be used to produce circular polarization?
Stack two Yagis to form an array with the respective elements in parallel planes fed 90 degrees out of phase
Stack two Yagis to form an array with the respective elements in parallel planes fed in phase
Arrange two Yagis on the same axis and perpendicular to each other with the driven elements at the same point on the boom and fed 90 degrees out of phase✓الإجابة الصحيحة
Arrange two Yagis collinear to each other with the driven elements fed 180 degrees out of phase
الشرح
Circular polarization requires two equal linearly polarized fields at right angles to each other and 90 degrees apart in time phase. Two Yagis on the same boom axis, rotated 90 degrees from one another with their driven elements at the same point along the boom and fed in quadrature, produce exactly that; parallel or collinear arrangements only give linear polarization or extra gain.