You're probably thinking about an Amphibious Force Command Ship
Navy Newsstand Photo
Such as the USS Blue Ridge (LCC-19) or her sister USS Mount Whitney (LCC-20). Both have heavy communications gear, but really a not a lot of radar. Also, they themselves are not heavily armed, relying on the escorts for AAW and ASW defense. They do have a CIWS for last-ditch defense.
Being a C3I asset, these would be targetted in the event of hostilities, but they are well protected by their support ships.
Trumpeter has some 1:700 scale kits of this class.