| 摘要 |
Antenna systems for transmitting electrical signals are provided which include a quadrifilar helix antenna. A first antenna feed is coupled to the quadrifilar helix antenna for exciting the radiating elements in phase quadrature. A second antenna feed is also coupled to the quadrifilar helix antenna for exciting the radiating elements in-phase. These antenna systems may be operated in either a helical radiation mode, where the antenna may be designed to radiate as a resonant quadrifilar helix antenna, or in a monopole radiation mode, where the antenna acts as the equivalent of a large monopole antenna. Additionally, the antenna systems may further include means for matching the impedance of the quadrifilar helix antenna to the impedance of either or both of the antenna feeds. |
