| 摘要 |
PROBLEM TO BE SOLVED: To keep a fixed gain despite the change of the peripheral condition such as a calling mode, etc., of a portable radio unit by reflecting the electric power fetched by a non-selection antenna at an open terminal of a switch means and radiating again a radio wave having the different phase from the direct wave to be sent to a selection antenna into a space. SOLUTION: A selection antenna 1 operates when a switch 5 is turned on, and the fetched electric power is supplied to a receiver 7 via a variable phase device 3 and the switch 5 and becomes effective. Meanwhile, the electric power fetched by a non-selection antenna 2 is reflected at an open part of a switch 6 after passing through a variable phase device 4 since the switch 6 is turned off. The radio waves are consumed by the device 4 but radiated again from the antenna 2 and inputted again to the antenna 1. The reflected radio waves have the the different phase from the direct wave that is sent to the antenna 1 and accordingly the radiation pattern of the antenna 1 is equal to that of a double element array antenna. Thus, a radiation pattern having high gain is obtained via the control of the device 4. |
