Not an expert, but here is my take: A phased array consists of many individual, non-directional antennas. The directionality comes by cleverly combining the sig

Not an expert, but here is my take: A phased array consists of many individual, non-directional antennas. The directionality comes by cleverly combining the signal of the antennas. If there is a jamming signal, all antennas would receive it. In theory, it would then cancel out when the signals are combined. The question is now: Before the signal is combined, is there any element which can be saturated by the large jamming signal? If so, you can jam. The phased array direction is tune-able, so I assume the combination is done in the digital domain. That means ADC in between, which can be saturated. So my guess is: yes.