The bent backfire zigzag--A vertically- polarized frequency-independent antenna

A new type of vertically-polarized, unidirectional frequency-independent antenna over ground is described. The antenna was first derived from the log-periodic (LP) zigzag by making a right-angle bend along the axis of the planar device. The result is a simple structure which has a maximum height slightly greater than one-quarter wavelength at the lowest frequency of operation. The simple, but useful analysis employed rests upon the assumption that the principles of operation of an LP antenna structure are related to those of a uniformly periodic antenna structure of the same type. This analysis is applicable to other types of frequency-independent antennas also. Experimental data are presented for a wide range of the parameters of the Bent LP Zigzag, and a design procedure is outlined.