Small antenna apparatus operable in multiple bands including low-band frequency and high-band frequency and increasing bandwidth including high-band frequency

A wireless communication apparatus comprising an antenna apparatus, the antenna apparatus comprising at least one radiator and a ground conductor,

• wherein each radiator comprises:
• a looped radiation conductor having an inner perimeter and an outer perimeter, the radiation conductor being provided with respect to the ground conductor such that a part of the radiation conductor is close to and electromagnetically coupled to the ground conductor;
• at least one capacitor inserted at a position along a loop of the radiation conductor;
• at least one inductor inserted at a position along the loop of the radiation conductor, the position of the inductor being different from the position of the capacitor;
• a feed point provided at a position on the radiation conductor, the position of the feed point being close to the ground conductor;
• and
• a dielectric block provided between the radiation conductor and the ground conductor, the dielectric block being provided in a portion where the radiation conductor and the ground conductor are close to each other, and the dielectric block provided along at least a part of the loop of the radiation conductor between the feed point and the capacitor,
• wherein each radiator is excited at a first frequency and at a second frequency higher than the first frequency,
• wherein when each radiator is excited at the first frequency, a first current flows along a first path, the first path extending along the inner perimeter of the loop of the radiation conductor and including the inductor and the capacitor,
• wherein when each radiator is excited at the second frequency, a second current flows through a second path including a section, the section extending along the outer perimeter of the loop of the radiation conductor, and the section including the capacitor but not including the inductor, and the section extending between the feed point and the inductor,
• wherein when each radiator is excited at the second frequency, a parallel resonant circuit is formed from:
• a capacitance between the radiation conductor and the ground conductor which are close to each other and between which the dielectric block is provided;
• and an inductance of the radiation conductor, and
• wherein each radiator is configured such that the loop of the radiation conductor, the inductor, and the capacitor resonate at the first frequency, and a portion of the loop of the radiation conductor included in the second path, the capacitor, and the parallel resonant circuit resonate at the second frequency.