The tech is already there, but the reason those antenna are not widely used is that they used to fall under ITAR, so no US companies want to touch those for civilian uses. Of course Turkey and China is not US so they don't give a damn about ITAR compliance, and so you can buy those anti jam antennas out of alibaba.

Brad Parkinson, the father of GPS and PNTAB, they've been trying to lobby the US government to remove ITAR from that technology so the civilian can benefit from anti jamming, and finally they managed to do it sometime last year. Now it falls under EAR