Strip transmission line having a tunable electric length

A strip transmission line system comprising

• (a) a strip transmission line for guiding a wave therein, said strip transmission line including
• (1) a strip-shaped inner conductor;
• (2) an outer conductor surrounding said inner conductor;
• (3) a ferrite coating carried on at least one of the conductors;
• and
• (4) at least one throughgoing slot in said inner and outer conductors for dividing said inner and outer conductors into at least two inner conductor sections and at least two outer conductor sections;
• said slots extending in a direction of wave propagation;
• and
• (b) current supplying means for applying a variable current to said inner and outer conductors to cause the variable current to flow in one direction in one of the inner and outer conductor sections and return in an opposite direction in another of said inner and outer conductor sections;
• the variable current generating a variable premagnetizing field within the strip transmission line between said inner and outer conductors to vary an electric length of the strip transmission line.