Fixed-Length Transmission Lines as Circuit Elements

The use of short-circuited transmission-line sections as wide-range resonant circuits in the 50-to 500-mc region is attended with one or more of these disadvantages: restricted tuning range with ordinary variable capacitors, limited choice of susceptance variation, poor impedance matching, and mechanical complexity. An analysis of an alternate method, using short, fixed-length transmission lines with a capacitor at each end, which overcomes these disadvantages, is carried through in normalized form to permit rapid graphical design of the lines and capacitors. The analysis is extended to include interstage coupling circuits and output circuits with a fixed coupling point.