Has anyone had a play with the Directional Discontinuity Ring Radiator antenna?

[VK3ZYZ]

file:///Users/imac/Documents/DDRR%20-%20Directional%20Discontinuity%20Ring%20Radiator.pdf
I see it has also been called "Direct Drive Ring Radiator"......

https://www.md0mdi.im/ddrr-an-antenna-for-small-spaces/

I remember looking at it many years ago.