| 摘要 |
PURPOSE:To well secure the communication near the surface wave line even with supply of a small amount of power by porviding the composite antenna consisting of several antenna elements featuring the strong directivity almost in parallel to the laying direction of the surface wave line. CONSTITUTION:Antenna elements 3 and 4 are distributed on straight line A, and the phase of the signal to be supplied to elements 3 and 4 is shifted by via phase shifter 5 with distance D between 3 and 4 selected at 1/2 wavelength of the supplied signal. As a result, a composite antenna is constituted with the strong directivity in the parallel direction to line A, and the feeding of power is carried out in the state under which the composite antenna is opposed to surface wave line 1 so that line A and the laying direction of line 1 may be parallel to each other substantially. Thus, the electromagnetic wave given from the antenna features the strong directivity in the direction parallel to the line, and accordingly the communication is well secured near line 1 even with supply of a small amount of power. |
