Antenna device and communication apparatus including the same

An antenna (12) includes: a base (2) having opposing first and second surfaces (2a, 2b) and opposing end surfaces; a radiation electrode (4) covering at least a portion of the first major surface (2b) of the base (2); a power terminal (5) disposed on the base (2) and operable to conduct signal power which is at least one of received and transmitted by the antenna; a mounting substrate (8) having spaced apart first and second major surfaces (8a, 8b); a first ground electrode (3) covering at least a portion of the second major surface (2a) of the base (2), wherein the base (2) is disposed on the mounting substrate (8) such that the second major surface (2a) of the base (2) is coupled to the first major surface (8b) of the mounting substrate (8) and a distance D is defined from the first major surface (2b) of the base (2) to the second major surface (8a) of the mounting substrate (8), and the radiation electrode (4) is electrically coupled to the first ground electrode (3) such that a gain of the antenna (12) is a function of the distance D.