| 摘要 |
<p>A wireless communication system and method for employing underground or low profile surface deployed current drivers (100) for inducing ground currents (108) in the earth which define loop antennas (127) for sending and receiving electromagnetic signals propagated through the atmosphere over a wide bandwidth. The system uses driver (100) whose impedance is adjusted so that it matches the impedance of a transmitter/receiver (19) connected thereto. The current driver is capacitively coupled to the surrounding ground (11) so that the current driver (100) and the earth (11) effectively function together as a vertical plane polarized antenna which propagates a vertically polarized electromagnetic signal. The system can be operated using either a single current driver or, where increased signal gain is desired, using an array or current drivers (16, 18) that are spaced in parallel. An undirectional vertically polarized signal may be produced by shortening the length of one (226) current driver conductor with respect to the other arm. Unwanted cancellation currents may be substantially eliminated from the region surrounding the current driver by positioning low conductivity materials (138) so as to extend into the flow paths of the cancellation currents.</p> |
