Extending the usable range of the 2-port shunt through impedance measurement

Wideband characterization of capacitors, inductors, ferrite beads, and power supply rail impedance is essential to optimizing the performance of most modern circuits. The 1-port reflection, 2-port shunt through, and 2-port series through S-parameter measurements performed with a vector network analyzer (VNA) are routinely used, and each technique supports a specific impedance magnitude range [1]. Many measurements are not contained within the range supported by a single measurement technique, leading to inaccurate results. Work-grounds often include the tedious process of splicing together multiple measurements for Wideband assessment. This often results in discontinuities and inaccurate results. This paper proposes a simple method for optimizing the measurement range to improve measurement fidelity while maintaining or increasing measurement bandwidth.