| 摘要 |
PURPOSE:To obtain a circularly polarized wave use antenna of a high gain and a small size, which scarcely causes fading, by providing a recessed part on the center part of a main passive reflector, and also adding a rotary mechanism part and a various phase shifter to a cross dipole feeding element. CONSTITUTION:A main passive reflector 4 is constituted of a metallic rim of the same cylindrical type, and a step-shaped circular recessed part 8 is formed on its center part in order to improve an antenna gain. As for a depth hs of the step, hs=-0.2lambda+AD1 (where 0.12<A<0.18) is desirable. On the other hand, this antenna is provided with a rotary mechanism 10 on a cross dipole 3 supporting part on the main passive reflector 4, as a countermeasure for fading, so that an attitude of said dipole element 3 is stabilized, and also a shape of a polarized wave can be corrected by a variable phase shifter 9. According to said constitution, the desired purpose can be attained. |
