Unusual features of the pseudo non-diffracting microwave vortex

A recently formulated, planar, circular-aperture field-distribution has been found to generate a radiation pattern exhibiting fundamentally-unusual features [1]. The aperture electric-field Eoarr , and magnetic field Hoarr were defined as linear-combinations of the W. W. Hansen\´s Moarr , and Moarr and Noarr basis vector-fields, and exactly satisfy therefore the Vector- Helmholtz equations for homogeneous, isotropic free-space [2]. Further, both the Eoarr and Hoarr fields generated by that aperture field-distribution include, in cylindrical coordinates, the axial E_z and H_z components, besides the E_r, E_phi , H_r, and H_phi tangential components. Also, most remarkably, the radial component S_r ^* of the complex Poynting Vector is identically-zero, everywhere on and above the aperture-plane, at all radial distances from the broadside-axis, and at all axial-distances from the aperture- * plane, while the broadside-directed axial component S_z ^* includes a very sharp center- lobe, with a maximum radius, on the aperture-plane, in the order of a half free-space wavelength. That center-lobe also contains most of the total power radiated from the whole aperture. The actual diffraction-pattern of that center-lobe, that actually is the main-beam of the generated radiation-pattern, is being determined using the ";Direct Electromagnetic Field Integration"; method, reported by Walter Franz in 1948 [3], and reviewed by Chen-To Tai in 2000 [4]. The planar, circular aperture is truncated, in that diffraction analysis, at an arbitrary maximum radius, by applying various edge-tapers of different shapes, with free-space all around the aperture-edge and behind the aperture- plane. The main beam of the generated radiation-pattern appears to have a wave-front in the form of a 3D helicoid-surface, becoming thus the microwave equivalent of an "optical vortex". The main beam is therefore - expected to propagate through free-space almost as a guided circular-waveguide mode would.