I think It should be able to target itself. some people and AI put PA on phase shield
The bit about phase shield is sort of the point though. This could work like PA, except that it would stay behind when the shield expires.
That means that 1 of these and 6 phase shields is 18 turns of stalling your opponent can't do a single thing about.
In addition, this card could also be protecting itself and 1 other permanent/creature at the same time, and if your opponent isn't packing perm control you can switch to just protecting creatures. It's capable of hard-countering all of the control cards in the game except for shields.
It isn't as bad as the above makes it sound though. As a permanent itself, it will need to survive at least one turn before it can protect itself, and using it every turn might get expensive after a while.
The concept in general makes for an interesting "try to guess what sort of control I'm going to use" mechanic, but it might be a little too effective at shutting down control decks in it's current form.