Small antenna apparatus operable in multiple bands including low-band frequency and high-band frequency with ultra wide bandwidth

摘要

A radiator includes a looped radiation conductor, a capacitor, an inductor, and a feed point on a radiation conductor. In a portion where the radiation conductor and a ground conductor are close to each other, a distance between the radiation conductor and the ground conductor gradually increases as a distance from the feed point along the looped radiation conductor increases. When the radiator is excited at a low-band resonance frequency, a current flows along a first path extending along an inner perimeter of the looped radiation conductor and including the inductor and the capacitor. When the radiator is excited at a high-band resonance frequency, a second current flows through a second path including a section extending along an outer perimeter of the looped radiation conductor, and the section including the capacitor but not including the inductor, and the section extending between the feed point and the inductor.

主权项

1. An 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 positioned 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; and a feed point provided at a position on the radiation conductor, the position of the feed point being close to the ground conductor, wherein the antenna apparatus is configured such that in a portion where the radiation conductor of each radiator and the ground conductor are close to each other, a distance between the radiation conductor and the ground conductor gradually increases as a distance from the feed point along the loop of the radiation conductor increases, 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, in the portion where the radiation conductor of each radiator and the ground conductor are close to each other, a resonant circuit is formed from: capacitance distributed between the radiation conductor and the ground conductor; and inductance distributed over 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 resonant circuit resonate at the second frequency.