A Single-Control Variable-Frequency Impedance-Transforming Network

The basis of the variable-frequency transformer to be described is the familiar transmission-line stub matching section. Although an infiiite number of structures may be found to produce the desired transformation at any one frequency, it is generally necessary to vary the lengths of the component lines to maintain matching when the frequency is changed. Mechanical complexities and electrical noise and losses in sliding contacts often make such methods undesirable. The particular solution to the stub matching problem described here is a structure which will maintain a perfect impedance match over a wide frequency range with the adjustment of a single reactance shunted across the load at the receiving end.