Measurement of Propagation Characteristics of Nonreciprocal Networks/Lines Using a Line–Line Method

In this article have proposed a new calibration-free line–line method for propagation constant (
$\gamma$
) determination of homogeneous nonreciprocal networks or lines with symmetric reflection property. To achieve our goal, wave-cascading matrices for impedance, amplitude, and phase changes for a line step from a homogeneous reciprocal network or line to a homogeneous nonreciprocal network or line (and vice versa). Two different approaches based on the proposed line–line method are proposed for unique extraction of
$\gamma$
in forward and backward directions. Measurements of
$\gamma$
for two reciprocal lines (waveguide straights at X-band and Ku-band with different lengths) and a nonreciprocal line (microwave phase shifter) were first carried out and then compared with measured
$\gamma$
of these lines by different methods to validate our method and monitor its accuracy.