| 摘要 |
PROBLEM TO BE SOLVED: To provide an omnidirectional antenna with a simple structure of a small outer diameter that has a wide operating frequency band and can change a tilt angle of a radiation beam within a vertical plane. SOLUTION: A half wavelength dipole antenna 3 is formed on a front side 2a and a rear side 2b of a dielectric board 2 at one edge of the narrow dielectric board 2 in the width direction, a microstrip line 6 and two parallel lines 5a and 5b acting like a feeding circuit 4 for supplying power to the half wavelength dipole antenna 3 are formed on the dielectric board 2, an earth plane 8 of the microstrip line 6 is arranged to extend along a vertical direction orthogonal to the width direction of the dielectric board 2, and parasitic elements 9a and 9b are arranged at positions apart in a direction respectively orthogonal to the front side 2a and the rear side 2b of the dielectric board 2 from around a center position of the dielectric board 2 in the width direction so that an electric center point P of the half wavelength dipole antenna 3 and electric center points M and N of the parasitic elements 9a and 9b have the same height position. COPYRIGHT: (C)2006,JPO&NCIPI
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