Material for antennas

[Victor_itsjustme]

Would it be possible in theory to develop a material with very slow velocity factor to build dipoles immersed in a slow velocity factor gas in order to make much smaller HF antennas?

 

[jedishrfu]

Welcome to PF!

Something like this description that talks about dipole length.

https://lowpowerlab.com/guide/rf-best-practices/velocity-factor/

Geometry might be a better scheme to shrink antenna size. There was a design for a fractal based antenna used in cellphones was quite compact.

https://en.m.wikipedia.org/wiki/Fractal_antenna

 

[marcusl]

Instead of using a high permittivity medium, you can load your antenna with lumped elements. You may have seen whip antennas on vehicles that have a large helical coil at their base.

Be aware that electrically small antennas have two drawbacks: first, they don’t couple as efficiently to EM waves as a full-sized antenna, and secondly, they generally have smaller bandwidth.