Antenna device and radio device comprising the same

A radio device comprising an antenna device and a circuit connected to the antenna device;

• said antenna device comprising:
• a substrate made of an insulation material and including a first major surface and a second major surface face;
• a ground electrode provided substantially on the whole of the first major surface of said substrate;
• an inverted F-shape antenna, comprising:
• a first radiation electrode disposed on the second major surface of said substrate and having a first open end and a first ground end;
• a first connecting electrode connecting said first ground end and said ground electrode;
• and a feeding electrode provided in the vicinity of the first ground end of said first radiation electrode and having one end connected to said first radiation electrode;
• a microstrip antenna, comprising:
• a second radiation electrode disposed on the second main surface of said substrate and having one open second end and a second ground end;
• and a second connecting electrode connecting said second ground end and said ground electrode;
• the second open end of said second radiation electrode of said microstrip antenna and said feeding electrode of said inverted F-shape antenna being capacitively coupled to each other;
• and
• a first direction through the first open end and the first ground end of said first radiation electrode being substantially perpendicular to a second direction through the second open end and the second ground end of said second radiation electrode.