| 摘要 |
The balanced, retractable dipole antenna comprises a first radiator element that is selectively extendable from, and retractable into, a mobile phone casing, a second radiator element, and a counterpoise that is electrically isolated from a printed wire board (PWB) of a mobile phone. The balanced, retractable dipole antenna further comprises a signal balancing means coupled between a signal source and at least the second radiator element and counterpoise to generate first and second signals, respectively. The first and second signals are substantially equal in magnitude but out of phase by 180 degrees. When the first radiator is extended, the first signal is transferred to the first and second radiator elements, and the second signal is transferred to the counterpoise. When the first radiator element is retracted, the first signal is transferred to the second radiator, while the second signal is transferred to the counterpoise and the first radiator element. The first and second signals produce balanced currents, thereby producing a symmetric radiation pattern.
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