1 research outputs found
X wave radiator implemented with 3D printed metamaterials
A radiator is presented, capable of generating
paraxial X waves over a 50% fractional bandwidth (7.5 β 12.5
GHz) in its radiative near field. X waves are localized pulses
formed by the superposition of Bessel beams with a common
cone angle. Quasiconformal transformation optics, a 2D variant
of transformation optics, is employed to find the inhomogeneous,
isotropic dielectric constant profile needed to convert the radiation of a monopole into a paraxial Bessel beam. An impedance
matching layer is applied to reduce reflections at the air-dielectric
interface of the device. The transformation and impedance
matching regions are implemented using rotationally symmetric
metamaterial unit cells that yield a spatially varying effective
dielectric constant. The resulting design is fabricated through 3D
printing, by combining parts made from three low-loss dielectric
filaments. The device is experimentally measured, and shows good
agreement with simulations. Its ability to generate paraxial X
waves when excited by a broadband pulse is verified