Microwave synthesis of Bessel, Bessel–Gauss, and Gaussian beams: a fully vectorial electromagnetic approach

Abstract

Bessel, Bessel-Gauss, and Gaussian beams have widely been investigated in optics in the paraxial approximation, under the frame of a scalar wave theory. Such approximations can hardly be applied in the microwave/millimeter-wave range, where the vectorial nature of the electromagnetic fields cannot be neglected, and experimental realizations for some of these beams appeared only recently. In this work, we discuss the generation of Bessel, Bessel-Gauss, and Gaussian beams through a fully vectorial electromagnetic approach. The field derivation of all these beams is first illustrated and numerical evaluations are then reported to compare their different propagation and diffractive behaviors. Finally, an innovative approach for realizing such solutions with planar microwave devices exploiting leaky waves is demonstrated through accurate numerical simulations.

Vortex circular airy beams through leaky-wave antennas

“…In order to study the entire excitation and emission process, we chose a reference CAB function to be radiated by a cylindrical antenna with maximum radius ρ max based on a platform similar to the one used in [33,46]. The relevant parameters are:…”

Finite-aperture Microwave Bessel Beams with Vortex Twisting, Fracturing, and Dynamic Phase-shift Control

“…They involve twisted reflectors [12], traveling waves [13], metalenses [14,15], metasurfaces [16,17], antenna arrays [18][19][20][21][22][23], and other structures. At the same time, the issue of beam divergence has received less attention [24][25][26]. Non-diffractive beam propagation occurs only in the near field, which is quite limited in the microwave band.…”