Canλ/4Radiators Be Really Isotropic?

[摘要] In search for isotropic radiators with reasonable quality Factor(Q), bandwidth, and efficiency, one looks for practical radiators witha typical resonant length ofλ/4. We present here a Green's function analysis in Fourier of aλ/4microstrip element and a far-fieldintegral method in configuration (real) space of single and dual U-shapedλ/4elements. Both solutions analytically prove that the powerradiation patterns are isotropic in nature (while the thickness and thewidth tend to zero), although the polarizations are not symmetrical inall cuts. It is also shown that the power isotropic U-shaped radiator,for which the surface current density is infinite, can be replaced byanother finite-size radiator, having finite-surface current density, suchthat its far-field is exactly the same as the far-field of the U-shapedisotropic radiator.

[学科分类] 电子、光学、磁材料