In search for isotropic radiators with reasonable quality Factor (Q), bandwidth, and efficiency, one looks for practical radiators\r\nwith a typical resonant length of ?/4.We present here a Green�s function analysis in Fourier of a ?/4 microstrip element and a farfield\r\nintegral method in configuration (real) space of single and dual U-shaped ?/4 elements. Both solutions analytically prove that\r\nthe power radiation patterns are isotropic in nature (while the thickness and the width tend to zero), although the polarizations\r\nare not symmetrical in all cuts. It is also shown that the power isotropic U-shaped radiator, for which the surface current density\r\nis infinite, can be replaced by another finite-size radiator, having finite-surface current density, such that its far-field is exactly the\r\nsame as the far-field of the U-shaped isotropic radiator.
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