In the previous report, we were looking for a core material that had the appropriate dielectric properties.
We were looking for a non-magnetic material that is rigid enough to work with and withstands temperatures of at least 160°C.
We have found that most of the materials within our reach were not very rigid but they did meet the rest of the necessary conditions.
We started to work with a PTFFE core which resisted the desired temperatures but it was too flabby to work with. So our team came to the solution of using a hollow PTFE core in order to stiffen it with a temporary inner sub-core made of a more consistent material. In this case we used a 100 micron thick stainless steel pin as a temporary stiffening agent.
This way we have managed to wind the antenna around a rigid core. After that, we have de-rigidized it by removing the internal temporary steel pin to finally obtain a flexible and resistant antenna, which meets the desired parameters.