Abstract: A radial slot antenna comprising a radial waveguide, which includes an upper plate, having a centroid and an edge region and provided with a plurality of radiating apertures, formed as slots in the upper plate, which develop around the centroid. The radiating apertures are arranged to form first and second radiating regions, which are distinct and radially separated by a dwell region without radiating apertures and wherein, in the first and second radiating regions, radially adjacent radiating apertures are separated from one another by a radial distance, the dwell region having a radial width greater than the radial distances of the radiating apertures in the first and second radiating regions. The slot antenna further comprises a signal feeder for supplying am electromagnetic field to assume, in the first and second radiating regions, opposite phases, so that the electromagnetic field emitted by the slot antenna can be expressed via Bessel functions.

Abstract: A radial slot antenna (1; 60) comprising a radial waveguide, which includes an upper plate (5), having a centroid (O) and an edge region (14) and provided with a plurality of radiating apertures (4), formed as slots in the upper plate (5), which develop according to an ideal annular pattern (16) around the centroid (O). The radiating apertures (4) are arranged in such a way as to form at least one first radiating region (31a) and one second radiating region (31b), which are distinct and radially separated by a dwell region (33a) without radiating apertures and wherein, in the first and second radiating regions (31a, 31b), radially adjacent radiating apertures (4) are separated from one another by a respective mutual radial distance, the dwell region (33a) having a radial width (?) greater than the mutual radial distances of the radiating apertures (4) in the first and second radiating regions (31a, 31b).

Abstract: Method for producing a stationary wave field of arbitrary shape comprising the steps of defining at least one volume being limited in the direction of the axis of propagation of a beam, of the type 0?z?L; defining an intensity pattern within the said region 0?z?L by a function F(z), describing the said localized and stationary intensity pattern, which is approximated by means of a Fourier expansion or by a similar expansion in terms of (trigonometric) orthogonal functions; providing a generic superposition of Bessel or other beams highly transversally confined; calculating the maximum number of superimposed Bessel beams the amplitudes, the phase velocities and the relative phases of each Bessel beam of the superposition, and the transverse and longitudinal wavenumbers of each Bessel beam of the superposition.

Abstract: Method for producing a stationary wave field of arbitrary shape comprising the steps of defining at least one volume being limited in the direction of the axis of propagation of a beam, of the type 0?z?L; defining an intensity pattern within the said region 0?z?L by a function F(z), describing the said localized and stationary intensity pattern, which is approximated by means of a Fourier expansion or by a similar expansion in terms of (trigonometric) orthogonal functions; providing a generic superposition of Bessel or other beams highly transversally confined; calculating the maximum number of superimposed Bessel beams the amplitudes, the phase velocities and the relative phases of each Bessel beam of the superposition, and the transverse and longitudinal wavenumbers of each Bessel beam of the superposition.