| 摘要 |
<P>PROBLEM TO BE SOLVED: To achieve an antenna that is manufactured easily and facilitates change of frequency characteristics or directivity. Ž<P>SOLUTION: A plurality of Yagi-Uda antennas having different frequency characteristics or directivity are arranged on a plane for superimposition. In an antennas except the one having desired directional characteristics or the frequency characteristics, antenna characteristics can be varied electrically by achieving clarification in a frequency band to be used by loading a variable device. The plurality of antennas are manufactured by a multilayer board in which an insulator layer and a conductor layer are laminated alternately. Further, a hole reaching a predetermined conductor layer is provided on the multilayer board, and the variable device is loaded so that electric connection is made to a conductor layer portion in which each one portion is exposed, thus avoiding interference between the variable device and the multilayer board. The hole may be a through-hole. Also, the variable device may be a variable reactor and may change a reactor by a switch. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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