| 摘要 |
<p>A wire-like or belt-like conductor is provided from a base (20a) to a first fold point (20b) at the tip side, and sequentially folded parallel not less than once at the tip side and the base side, forming a first element (20d); the conductor is split at the first fold point (20b) and the split conductor is, similarly, sequentially folded parallel not less than once at the tip side and the base side, forming a second element (20f). Then, the effective length from the base (20a) to the tip (20c) of the first element (20d) is set to a quarter of the wavelength of a first frequency (f1), and the effective length from the base (20a) to the tip (20e) of the second element (20f) is set to a quarter of the wavelength of a second frequency (f2). A folded antenna element (10), comprising a wire-like or belt-like conductor which is provided in a direction from the base to the tip side, the conductor being folded at least once at the tip side and arranged parallel to the direction, is made cylindrical; a rod-like antenna element (12) is provided so as to be freely movable in the axial direction of the folded antenna element (10); and, in an extended state, the base side of the rod-like antenna element (12) becomes inserted to the tip side of the folded antenna element (10) and is capacitance-coupled thereto by a large coupling capacitance (C). The effective length of the folded antenna element (10) from the base to the tip is a quarter of the wavelength of the first frequency (f1), and three quarters of the wavelength of the second frequency (f2). In the extended state, the effective length from the base of the folded antenna element (10) to the tip of the rod-like antenna element (12) is a quarter of the wavelength of the first frequency (f1), and three quarters of the wavelength of the second frequency (f2). <IMAGE></p> |
