| 摘要 |
The present invention provides an antenna system having one or more of the following characteristics or features: Disguised Antenna System; Dual band operation: Broad band operation; Isolation between transceivers to eliminate the need for change over switches or relays; and Built in broadcast coupler The foregoing can be provided by decoupling the antenna mast for multiple bands by use of a quarter wave decoupling stub or by the use of a frequency relative trap. As a result the antenna has multiple resonances simultaneously. The foregoing also can be accomplished by selecting antenna mast lengths that are harmonically related to provide a single element with multiple resonances without external devices. A diplexer comprising the combination of high and low pass filters and a broadcast coupler can be connected to the antenna feed point with transceivers operating in the different bands being connected to the high and low pass filters. The simultaneous multiple resonances ensure a matched impedance at the antenna feed point so that when a communications device is connected by a length of coax to the antenna feed point the matched impedance will be maintained at the feed point regardless of the length of the coax. |
