Here's the short description of the 6 element array at WW2Y that K2WI
mentioned a few
days ago on this reflector.
The array consists of two 3 element endfire arrays side by side spaced
1/2 wavelength
apart and fed in phase. It 's similar to having two yagis stacked horizontally
fed in phase.
Each element of the 3 element endfire array are spaced 1/4 wavelengths
apart, fed with
progressive phase shift of 90 degrees and a binominal current distribution of
1: 2 : 1.
Thus the center elements of the endfire arrays has twice the current compared
to the
outside elements. Each element consisted of a inverted 'L' with the horizontal
section point-
ing to its broadside neighbor. There are two power splitting techniques used
to feed all 6
elements. First the 90 degree hybrid coupler that deliverd 3 outputs with
binominal currents
with phases of -90, 0 , 90 degrees. Second, each of the 3 outputs fed into the
wilkinson power divider that fed the broadside neigboring pair of elements
that are in phase. Since
the broadside pair of elements are in phase and have the same feedpoint
impedances, the
wilkinson power divider works very well for this application. The measured
current of
all 6 elements were within a few percent of what they should have been without
any tweaking.
The total space required for the entire array without the ground system 1/2
wavength
square , with the ground system would be twice that amount.
More on this later.
Peter WW2Y
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