On the Multimode Resonant Null Frequency Scanning Antennas

A survey of developments and milestones of null scanning antennas (NSAs) is comprehensively presented. The general design approaches to NSA are systematically classified and insightfully anatomized. Furthermore, several designs are presented to introduce the developments, operation mechanism and design approaches of multi-mode resonant null frequency scanning antennas (NFSAs). Finally, possible developing trends and application scenarios of NFSAs are prospected. This paper is expected to provide beneficial design guidelines to the scientific researches, as well as the engineering developments of NFSAs.