effect of magnetic field on AUT

I have a small question, suppose we have an AUT
working on lets say 2.4 GHz, bandwidth is around may be 100 MHz.
and it has a high dielectric

these values are arbitrary though.

So what happens to the radiation pattern if we bring a high magnetic field near it
suppose we enclose the antenna in a high magnetic field. so what will happn to the
shape of the radiation pattern and on different parameters.

i read about it and found I think gain will remain the same .. power etc ...

but there is definetly change in the radiation pattern.

THANX