Experimental demonstration of highly localized pulses (X waves) at microwave frequencies

A device that radiates transverse magnetic Bessel beams in the radiative near field is reported. The cone angle of the emitted radiation remains constant over a wide frequency range (18–30 GHz), allowing highly localized pulses (X waves) to be generated under a broadband excitation. The design process, based on ray optics, is discussed. Both frequency and time domain experimental results for a prototype are presented. The measured fields show close agreement with simulation results, and demonstrate the radiator's ability to emit X waves within its nondiffracting range.