A multi-antenna structure includes: a substrate; a ground plane disposed on the substrate; a signal feed mechanism; a first antenna coupled to the ground plane via the signal feed mechanism; a second antenna coupled to the ground plane via the signal feed mechanism; and an isolator electrically coupled to the ground plane and disposed between the first antenna and the second antenna, the isolator including: a first side wall and a second side wall that define a slot; a short coupled to the first side wall and to the second side wall to define a first end of the slot; and a capacitor configured and disposed to be coupled to the first side wall and to the second side wall to define a second end of the slot.