| 摘要 |
PROBLEM TO BE SOLVED: To provide a phase difference feed antenna that uses two radiation elements and has cardioid directivity. SOLUTION: A two-element antenna is comprised by disposing in parallel radiation elements 11a, 11b each having a length of approximatelyλ/2 while spacing appropriatelyλ4 therebetween. A power feeding signal is then inputted to an input terminal 22a of a differential power distribution circuit 21, a signal output from a distribution terminal 22b having a great distribution ratio is supplied to a power feeding point 12a of the radiation element 11a via a phase circuit 23 having a phase delay of appropriately 25°, for example, and a signal of a small distribution ratio output from a distribution terminal 22c is supplied to a power feeding point 12b of the radiation element 11b. The distribution ratio in the distribution terminals 22b, 22c of the differential power distribution circuit 21 is set to 3.35:1, for example, to compensate increase/decrease in an induction current caused by the mutual influence of the radiation elements 11a, 11b so that currents induced by the radiation elements 11a, 11b become the equal amplitude, thereby obtaining cardioid directivity. COPYRIGHT: (C)2005,JPO&NCIPI
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