| 摘要 |
<p>A portable radio unit (1) comprises a case (2), a cover (3) attached to the case (2) and adapted to open and close, sensor means (7) for determining whether the cover (3) is open, a dipole antenna (5) attached to the cover (3), feeder means (4a, 4b, 6a, 6b) for feeding the dipole antenna (5), and control means (8) for controlling the feeder means (4a, 4b, 6a, 6b) according to whether the cover (3) is open or closed. Alternatively, the portable radio unit (1) comprises a resonator (9) provided on the case (2) such that the resonator (9) is close to the dipole antenna (5) when the cover (3) is closed. The dipole antenna (5) is connected to feeder means (6) through a first or second matching circuit (12, 13) depending on whether the cover (3) is open or closed.</p> |
