Meteor echoes at ultra-high frequencies

摘要: It is proposed that, at ultra-high frequencies, underdense meteor echoes have an effective scattering length L, which much less than a Fresnel zone. Consequently, UHF meteoric may be analyzed in terms of Fraunhofer diffraction theory, resulting relaxation the requirement that trail perpendicular to radar line-of-sight before echo can received. Formulas for back-scattered power, time duration, and rate are deduced.