| 摘要 |
PROBLEM TO BE SOLVED: To provide a monopole antenna which can remarkably improve a reflection characteristic and also can provide a broad operational frequency band. SOLUTION: The antenna includes a dielectric board 2 erected on a grounding surface 1, a radiation conductor 3 provided vertically along the surface of the board 2 to be connected at its lower end to a power supply line 7, and a capacitor for canceling an inductive reactance component of the radiating conductor 3. The capacitor is provided between the vicinity of the power supply point of the radiating conductor 3 and the grounding surface 1. As such a capacitor as to adjust an impedance, a chip capacitor 5 connected at its one end to the vicinity of the power supply point of the radiating conductor 3 and connected at the other end to a grounding electrode part 4 is suitable. Since the monopole antenna has such an arrangement, return loss can be remarkably reduced at a resonance frequency and in the vicinity thereof. COPYRIGHT: (C)2003,JPO
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