Patent ID: 6822620
Filing Date: 2004-11-23
Classification: H01Q

Abstract:
A helical antenna comprising:a base body made of a dielectric material or a magnetic material; and a helically-configured conductor formed at least either on a top surface of the base body or in an interior thereof, wherein, in the base body, a thickness a (mm) is kept in a range of 0.3&lE;a&lE;3 (mm); a length b (mm) is kept in a range of 5&lE;b&lE;20 (mm); and a relative dielectric constant &egr;r is kept in a range of 3&lE;&egr;r&lE;30 or a relative magnetic permeability &mgr;r is kept in a range of 1&lE;&mgr;r&lE;8, and also a number of winding x (turn) of the conductor is kept in a range of 3&lE;x&lE;16, and wherein a resonant frequency f (MHz) and a width w (mm) of the conductor satisfy following formulae (1) and (2), respectively: f=Ax+By+C(MHz)â€ƒâ€ƒ(1) w=Dx+E (mm)â€ƒâ€ƒ(2) wherey represents a width (mm) of the base body; and A, B, C, D, and E each represent a constant which is determined in accordance with the thickness a, the length b, and the relative dielectric constant &egr;r or the relative magnetic permeability &mgr;r of the base body.