| 摘要 |
PROBLEM TO BE SOLVED: To provide a miniaturized and lightweight helical antenna which suffers only a small change in resonance frequency even when a conductor width is dispersed. SOLUTION: In the helical antenna, a helical conductor 4 is provided on the surface of and/or inside a base member 2 the thickness (a) of which is 0.3≤a≤3 (mm), the length (b) is 5≤b≤20 (mm), and the dielectric constantεr is 3≤εr≤30. The number (x) of winding of the conductor is 3≤x≤16 (winding), and the resonance frequency (f) and width (w) of the conductor fulfill a formula (1) f=Ax+By+C (MHz) and a formula (2) w=Dx+E (mm), wherein (y) is the width of the base member and A to E are constants determined by the thickness (a) of the base member, its length (b) and its dielectric constantεr. Thus, miniaturization is attained and even when the width (w) of the conductor is dispersed, the change in resonance frequency (f) is suppressed small. COPYRIGHT: (C)2003,JPO
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