Experimental generation of propagating Bessel beams with a low-profile leaky radial waveguide

The generation of Bessel beams using a leaky radial waveguide is presented. The radial waveguide consists of a capacitive sheet over a ground plane. It supports an azimuthally invariant leaky-wave mode whose normal electric-field component is a truncated, zeroth-order Bessel function. A vector field approach is employed to derive design relations for the radial waveguide, in contrast to previous works on Bessel beams based on scalar wave theory. A prototype is presented. Electric field measurements and their respective Fourier transforms validate the operation of the prototype as a Bessel-beam launcher. The proposed structure can be used for generating arbitrary zeroth-order propagating Bessel beams at microwave or millimeter-wave frequencies.