It would be interesting to see the same antenna produced from a more consistent dielectric material than generic FR4. Meanwhile, if you are interested in microwave RF design, take a look at ...

Antenna tuning at HF frequencies is something ... Here is where some of the Black Art of high frequency RF design is laid bare, with everything explained through a series of use cases.

A shape-changing antenna would enable communications ... To solve the problem, the team, led by RF and microwave design engineer Michael Sherburne, had to invent a new form of power line.