Frequency-variable antenna circuit, antenna device constituting it, and wireless communications apparatus comprising it

摘要

An antenna device comprising an antenna element disposed on a mounting board separate from a main circuit board, a coupling means disposed on the mounting board such that it is electromagnetically coupled to the antenna element, and a frequency-adjusting means disposed on the mounting board such that it is connected to the coupling means, the antenna element comprising first and second strip-shaped antenna elements integrally connected for sharing a feeding point, the second antenna element being shorter than the first antenna element; the coupling means being formed on a dielectric chip attached to the mounting board, and having a coupling electrode electromagnetically coupled to part of the first antenna element. The frequency-adjusting means comprises a parallel resonance circuit comprising a variable capacitance circuit and a first inductance element, and a second inductance element series-connected to the parallel resonance circuit.

主权项

1. A frequency-variable antenna circuit comprising:
a first antenna element; and a frequency-adjusting means coupled to said first antenna element via a coupling means, said frequency-adjusting means comprising:
a parallel resonance circuit comprising a variable capacitance circuit and a first inductance element connected in parallel to said variable capacitance circuit; anda second inductance element series-connected to said parallel resonance circuit, wherein the frequency-adjusting means is capacitively connected to the first antenna element via the coupling means.