Balanced Backfire Zigzag Antennas

摘要

Linearly polarized backfire antennas are described which have high front-to-back ratio and very low sidelobes. The backfire radiation is produced from a meandering conductor. The principal directional characteristics can be determined by using linear array theory. When the conductor is periodic this can be related to a series expansion of the fields in space harmonics. The radiation properties of periodic backfire zigzags are compared to the end-fire type previously reported. Bandwidth limitations on the backfire periodic zigzags are readily extended by tapering the structure to produce a log-periodic antenna. Measured patterns and impedance of several log-periodic zigzag antennas illustrate how the performance is related to that of the periodic structures. (Author)