An Innovative Direct NF-FF Transformation Technique with Helicoidal Scanning

<table>Far-field pattern in the plane at <svg height="13.1375" id="M131" style="vertical-align:-0.1638pt" version="1.1" viewbox="0 0 53.724998 13.1375" width="53.724998" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
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q0 51 19 93.5t49 70t69.5 47t77.5 28t76 10.5q0 30 -11 39t-54 12v28h218zM335 118v429q-34 -2 -67 -13.5t-63.5 -35t-49.5 -65.5t-19 -96q0 -56 18.5 -99t49 -67.5t63.5 -37.5t68 -15zM418 547v-429q35 2 67.5 14t63.5 35.5t50 66.5t19 99t-19 99t-50 66.5t-64 35t-67 13.5
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t96 -62.5q53 0 78 45.5t25 105.5q0 68 -35 116t-99 48z" id="x36"></path></g><g transform="matrix(.017,0,0,-.017,40.452,12.875)"><path d="M241 635q53 0 94 -28.5t63.5 -76t33.5 -102.5t11 -116q0 -58 -11 -112.5t-34 -103.5t-63.5 -78.5t-94.5 -29.5t-95 28t-64.5 75t-34.5 102.5t-11 118.5q0 58 11.5 112.5t34.5 103t64.5 78t95.5 29.5zM238 602q-32 0 -55.5 -25t-35.5 -68t-17.5 -91t-5.5 -105
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</svg>. Solid line: exact field. Crosses: reconstructed via the direct helicoidal NF-FF transformation.</table>

International Journal of Antennas and Propagation

fig4

Figure 4

Figure 4: An Innovative Direct NF-FF Transformation Technique with Helicoidal Scanning 