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The formula in the question is taken from page 44 of a book called The Theory of Electromagnetic Wave Propagation by CH Papas. The text says that the formula describes the radiation pattern for a center driven wire antenna. Radiation patterns normally show a graph of relative intensity which isn't the same thing as efficiency. For transmitting, the ...


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It isn't. Gain in the broadside (θ=0) direction isn't "efficiency". A half-wave dipole doesn't maximize that parameter, even among dipoles; it increases until roughly 1.25 wavelengths, then decreases, then generally increases again, in an oscillating way. There are nice things about half-wave dipoles (a convenient, easily-matched impedance and a ...


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I'm not sure if this is the correct answer or not: At varying electric lengths, at any moment in time, one part of the antenna is producing the wanted field(s) and another part might be producing a canceling field(s). With a half wavelength, all you get is the wanted field and no canceling field. The canceling field (I call it that because it works against ...


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