| 摘要 |
<p>An arrangement for radiating RF signals from a radio transmitter which comprises an antenna and an electrical isolator connected to the antenna for isolating the antenna from the transmitter, wherein the isolator includes a conducting elongate element along which RF electrical signals are fed in use, and further conductors which are not electrically connected to the elongate element, the further conductors comprising first and second conducting layers arranged with the elongate element extending between them and third and fourth conducting layers arranged with the first and second layers extending between them, the further conductors forming in use an electromagnetic shield to RF electrical signals passing along the elongate element, the antenna being connected to the elongate member of the isolator. <??>The layers of the isolator may be planar. The total combined effective electrical length of the first and third layers along an axis of the isolator and the total combined effective electrical length of the second and fourth layers along the axis of the isolator may be or approximate to 0.5 lambda , where lambda is the mean wavelength of RF electrical signals to be passed in use along the elongate element. The effective electrical length of each of the first, second, third and fourth layers along the axis may be or approximate to 0.25 lambda . <IMAGE></p> |
