Generation of a long-nondiffractive-range leaky-wave Bessel beam through an open-stopband mitigation technique

Bessel beams maintain their focusing properties only up to a finite distance known as nondiffractive range. Efforts are needed in any frequency range to increase this distance as much as possible. In this work, an innovative leaky-wave wideband Bessel-beam launcher with a very extended nondiffractive range has been designed in the microwave range by exploiting an open-stopband mitigation technique. In particular, at the working frequency of 30 GHz (λ = 1 cm), an impressive nondiffractive range of 10 m has been reached with a planar, cost-effective, single-feeder structure having an aperture diameter of about half a meter. Full-wave results show that the launcher radiates Bessel beams at a distance that is 20 times its aperture diameter.