Placing a perfectly conducting surface at will cause the right moving wave to be perfectly reflected at this surface. Then the wave flowing out the left side will be a linear superposition of the left moving wave generated by the probe and the reflected wave. Since the parallel component to the electric field at the surface of a perfect conductor must vanish, the reflected wave will come back
out of phase. We can write the left moving wave as
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(16) |
and it is easily seen that the reflected wave must be
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(17) |
so that at ![]() ![]()
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(18) |
The maximum amplitude case occurs when there is constructive interference
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(19) |
since the amplitude doubles, the power is then increased by a factor of four. For this maximum power case, the radiation resistance is given by
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(20) |
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(21) |