ANTENNA FOR PORTABLE RADIO

摘要

An antenna for portable radio in which a high gain and a wide band are realized. An inverted L-shaped antenna (10) is a feeding element having one end part connected electrically with one plate surface of a circuit board (12) through a feeding point. The circuit board (12) is the substrate of circuit of a portable radio and connected with circuit components including the inverted L-shaped antenna (10). A planar antenna (14) is provided on the plate surface of the circuit board (12) opposite to the side being connected with the inverted L-shaped antenna (10) and it is a parasitic antenna having an electric length in the longitudinal direction substantially equal to one half of the wavelength of a radio wave through which the portable radio communicates. Dimensions and the mutual distances of the inverted L-shaped antenna (10), the circuit board (12), and the planar antenna (14) are adjusted to specified values, and the self impedances of the inverted L-shaped antenna (10) and the planar antenna (14) are varied along with the mutual impedance of the inverted L-shaped antenna (10) and the planar antenna (14).