Nonreciprocal phase-shift CRLH transmission lines using geometrical asymmetry with periodically inserted double shunt stubs

A new method of controlling phase nonreciprocity is proposed in composite right/left handed transmission lines with normally magnetized ferrite substrate. In the present approach, geometrical asymmetry is employed for the nonreciprocal phase control by changing electrical lengths of double shunt stubs inserted on both sides of the center microstrip line. To verify the basic concept, the nonreciprocal phase characteristics are investigated numerically and experimentally by changing the stub lengths for epsilon-negative high-pass structures keeping with the cut-off frequency fixed.