A DIELECTRICALLY-LOADED ANTENNA

摘要

A dielectrically-loaded multifilar antenna has an electrically insulative solid core bearing an antenna element structure having four pairs of substantially helical radiating elements spaced apart around a central axis of the antenna. Each pair of oppositely located antenna elements forms part of a conductive loop having an effective electrical length in the region of N guide wavelengths at the operating frequency where N is an integer and is at least 2. Typically, each helical element executes substantially a full turn around the axis on the outer surface of the core. The antenna offers an improved gain-bandwidth product compared with typical prior dielectrically-loaded multifilar helical antennas, and a 3dB beamwidth of at least 90° for circularly polarised radiation.