| 摘要 |
913,020. Aerials. COMPAGNIE GENERALE DE TELEGRAPHIE SANS FIL. Jan. 10, 1961 [Jan. 14, 1960], No. 1026/61. Class 40 (7). An aerial system capable of radiating or receiving circularly polarized waves to or from any direction within a considerable solid angle comprises two serially-connected coaxial helical coils formed one within the other and such that the outer coil consists of from one to four turns and the inner coil a greater number of turns on a core member of ferro-magnetic material. The length of the system is smaller than the working wavelength. In the embodiment shown the system is fed by a coaxial line and the inner conductor 2 of the line is coupled to a two-turn outer helix 1 of diameter one quarter of the working wavelength and length one-third of this length. At its outer end this coil is joined to a ten-turn inner coil 3 wound round a rod 4 of ferro-magnetic material. The rod 3 is supported from the end of the coaxial line by insulator 5 and the inner end of coil 3 is connected to the outer conductor 6 of the line. The diameter of coil 3 may be a tenth of the working wavelength. The system is said to have a diagram with a 60 degrees apex angle to 3 db. points and to have a factor of ellipticity better than 0.7 within an apex angle of 80 degrees. |
