| 摘要 |
<p>Antenna apparatus comprises dipole antenna (14) arranged proximate to a surface of metal housing (11) of radio device circuit (12) and having two quarter wavelength elements (21, 22) having opposite end portions being feed points (23, 24), short-circuit element (15) short-circuiting the quarter wavelength elements (21, 22), and coaxial feed line (16) having outer conductor (25) and central conductor (26) having one ends connected to the feed points (23, 24), and connecting the feed points (23, 24) to radio device circuit (12). The coaxial feed line (16) is arranged along part of the quarter wavelength element (21) and part of the short-circuit element (15) and branched from central portion of the short-circuit element (15). The outer conductor (25) is partially connected to the quarter wavelength element (21) and short-circuit element (15). Currents leaked onto the feed line (16) and flowing through the two quarter wavelength elements (21, 22) are also divided to the short-circuit element (15). The currents are mixed at a position at which the coaxial feed line is branched and leaked into the outer conductor of the coaxial feed line. The leaked currents are almost opposite in phase to each other. it element are almost opposite in phase to each other. Thus, the currents cancel each other and the leak current becomes zero. <IMAGE> <IMAGE></p> |
