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

摘要

A radiator is provided with a looped radiation conductor, a capacitor, an inductor, a feed point on the radiation conductor, and a dielectric block provided in a portion where the radiation conductor and the ground conductor are close to each other. At a low-band resonance frequency, a current flows through a path extending along an inner perimeter of the loop of the radiation conductor and including the inductor and the capacitor. At a high-band resonance frequency, a current flows through a path including a section extending along an outer perimeter of the loop of the radiation conductor, including the capacitor but not including the inductor, and extending between the feed point and the inductor, and a parallel resonant circuit is formed from: a capacitance between the radiation conductor and the ground conductor between which the dielectric block is provided; and an inductance of the radiation conductor.