Antenna coupler

#The present invention relates to an impedance coupling device and more particularly to an antenna coupler for use in matching an antenna to a high power transmission line so to enable a high power signal to be radiated with maximum efficiency.

#It is well known that an antenna must be tuned or matched to its transmission line for the frequency of the signal being radiated for the purpose of achieving maximum efficiency. At low and medium signal powers, such tuning or matching presents no serious problems. Such coupling can be achieved in a variety of ways, for example, by adjusting capacitor values and by the use of tuning coils. Electronic circuitry is also available for detecting circuit conditions and automatically adjusting the coupling device so as to produce the most effective matching of the antenna with the transmission line for the particular signal under any given conditions.

#It should, of course, by borne in mind that the matching of an antenna with its feed line may require different adjustments, depending upon weather conditions and the surrounding conditions of the earth as well as when the signal frequency is varied.

#The invention will now be described merely by way of illustration with reference to the accompanying drawings, in which:

#FIG. 1 is a perspective illustration of a coil of one embodiment of an antenna coupler according to the present invention;

#FIG. 2 is an enlarged perspective illustration partly in section of part of the coil shown in FIG. 1 and also showing one of the fluid actuated cylinders mounted on that coil;

#Referring first to FIG. 1 of the drawings, it will be seen that there is shown therein a generally triangular electrically conductive coil generally indicated by the legend 10. The coil 10 is made up of a plurality of turns, each of which in turn comprises three linear segments 12.

#The linear segments 12 of each of the turns of the coil 10 are joined together at corners 14 so as to form a continuous triangular shaped helix. The size of the segments 12 and of the coil 10 will of course depend upon the signal frequency and the desired power output that the coil is required to handle but, in general, such a coil will be metallic and will typically be formed of copper in either cylindrical or rectangular bar stock form.

#It will of course be appreciated that the triangular configuration shown is merely for the sake of illustration. The coil 10 could equally well be square or indeed any other shape which is convenient for manufacturing purposes. In general, however, each turn of such a coil will generally have a polygonal configuration formed from a plurality of linear segments.