Impedance ratio varying device

#It has long been an object of the prior art to obtain a match for impedance of an RF source to that of a line or antenna. See U.S. Pat. No. 2,855,599 as a teaching of a way to arrive at this object and for the reasons such is desirable.

#However, while this has been a long standing object, no one is known prior to this invention to have found a practical, inexpensive and compact means of packaging such elements to permit universal economical utilization. It is therefore the principal object of this invention to obtain a compact concentric operative relationship of loading coil and coupling coil for impedance matching of an RF source to a line or antenna.

#FIG. 1 is a simple schematic design of an impedance matching circuit according to this invention;

#FIG. 2 is a plan view with some elements partially shown in cross-section for clarity of element relationships of a package concept for the circuit of FIG. 1 in accordance with this invention; and

#FIG. 3 is an end view along lines 3--3 of FIG. 2.

#With more particular reference to FIG. 1 there is shown a loading coil 10 operatively related to a coupling coil 12 such that varying the resolution ratio of coils 10 and 12 may be scheduled by a commutator 14 between the line and ground terminals 16 and line 18 respectively. With such circuits a pair of terminals 20, 22 connect a signal source or receiver to the coupling coil.

#Such structure makes it possible to find a specific match for the transmission line and load. Specific utility is found for this invention in impedance matching an antenna and/or a transmission line to an RF source.

#Turning now to FIG. 2 there the structure is shown by which this invention may be realized. Specifically, the loading coil 10 is mounted about an insulator 24. A shaft 26 is connected to the insulator 24 to rotate same. As seen, the shaft is supported by a bearing block 28 in an end piece and held thereto by a retaining ring 30. Shaft 26 is connected to a ground source as by a sliding contact (not shown) or any other well known means available to one skilled in the art. This could even be by an end frame where one does not, as here, use an end frame 32 to also support commutating wheel shaft 34.