| 摘要 |
PROBLEM TO BE SOLVED: To provide a composite antenna which is free of the reduction in gain of a first antenna 18 for a first frequency band even when first and second antennas 16 and 24 different by frequency bands are provided. SOLUTION: A conductive tape 32 is wound around insulating sheaths of an outer conductor 28a of a first coaxial line 28 connected to a first antenna 18 and an outer conductor 30a of a second coaxial line 30 connected to a second antenna 24 to capacitively couple them, and a total path length resulting from summing up a path length a from a capacitive coupling position to a position where the outer conductor 28a of the first coaxial line 28 is electrically connected to a first ground plate 12 of the first antenna 18, a path length b from the capacitive coupling position to a position where the outer conductor 30a of the second coaxial line 30 is electrically connected to a second ground plate 26 of the first antenna 24, and a length from the position of the second ground plate 26 to which the outer conductor 30a of the second coaxial line 30 is electrically connected, to the most distant position of the second ground plate 26 is an effective length of an approximately half wave of the first frequency band. COPYRIGHT: (C)2011,JPO&INPIT |
