I'm used to seeing log-periodic antennas, the classic "TV antenna" that one can still see on the tops of houses or older buildings. There is a long row of transversely-mounted elements, connected in some way along the center axis, whose length and spacing vary in a log-periodic fashion.
From: https://www.scannermaster.com/CLP_5130_1N_Log_Periodic_Antenna_p/40-541274.htm
But when I was doing research before writing this question I came across this log-periodic antenna.
Does this design have a name? It's one continuous conductor, and serpentine with each successive element connected in the opposite direction than the previous. Why? is the serpentine nature important for the way that it functions?
above: Cropped detail of "Log-periodic shortwave antenna besides the old Varberg Radio Station, Sweden" From here. Right click and open in a new window for larger view.
above: "Log-periodic shortwave antenna besides the old Varberg Radio Station, Sweden" From here.
Best Answer
A interesting structure for sure and one can learn a lot by researching SE answers.
The antenna type you illustrate is called a Tapered Ladder Log-Periodic wedge antenna. A patent by RH du Hamel et al from 1963 shows the structure you seek in figure 7 it is similar to the Zig-Zag Log-Periodic antenna. The patents are mostly from the 1940's to 1960's and the benefits of the ladder/zig-zag style have been described as having structural and phasing benefits. A patent from 2003 still shows the general configuration as prior art so it is not forgotten.
Some of the patents and literature show a additional tapered feed-line that is used to drive the ladder style elements at a points away from the centreline at some suitable matching impedance, the desired configurations seem to use the structure or the inter element connections for excitation and phasing.
Here is a forum thread with a lot of collected data by someone investigating indoor antennas and a 1960's magazine article is mentioned. Simulation, calculation and construction ideas are discussed.
What looks very similar to your sample is illustrated on a general Log-Periodic description page.
A vertical element earth reflected monopole type is mentioned in a patent showing alternative top-hat and trapezoidal geometries.
The geometries of Log-Periodic antennas are many. From long wave to micro-scale they do however share much in common.