I have a very difficult antenna design/installation challenge. I need to install an VHF antenna (118 to 140 MHz) into a nearly all carbon fiber glider. The radio provides 5 watts and 50 ohm, and most signals of interest are vertically polarized.
Since this is a glider, and aerodynamic efficiency is the highest priority, mounting an antenna external to the hull is not considered an acceptable option. So the options seem to be:
Mount a rubber ducky style antenna in the lower front of the aircraft, below the cockpit center-line, which is the only place on the aircraft that is fiberglass. But the maximum vertical height in this region is only about 5 inches and it there is a carbon fiber bulkhead above and behind this small zone.
Mount a rubber ducky style antenna in the upper half of the cockpit, where the antenna would at least have some line of sight forward, to the sides, and upward. This would at least allow the antenna to be mounted fully vertically.
I've considered a full wave loop around the outside of the fuselage. But my research into this says that even if the antenna is isolated from carbon fiber skin with some dielectric (like Kapton tape), I'll end up with RF coupling and reflections that cancel most of the signal.
So, with all of this said, I'm wondering if there is an approach I'm missing, or if this is just a bad situation and an electrically short monopole antenna is about the best that could be done.