| 摘要 |
PROBLEM TO BE SOLVED: To obtain a helical antenna also suitable as an antenna receiving the radio waves in high frequency band by enhancing the antenna gain and the rigidity even if an outer coiled conductor is made thin and making the antenna compact. SOLUTION: The outer coiled conductor 13 of a helical antenna 11 comprising a straight wire-shaped inner conductor 12 and an outer coiled conductor 13 is a wire of two-layer structure obtained by integrating an outer circumferential material 13b of high conductivity metal such as copper on the outer circumference of a core material 13a of high rigidity metal such as stainless steel by plating or cladding, and a coil is formed by winding the wire densely while providing an insulating coating 14 on the surface. Alternatively, the insulating coating is not provided and a coil is formed by space winding having a minute coil gap. COPYRIGHT: (C)2008,JPO&INPIT
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