Minimum of two-port voltage and power gain under varying terminations: Semi-analytical method and application to biotelemetry systems

We analyze the structure of the level sets of voltage gain and transducer power gain in two-port systems and based on the findings, present a semi-analytical method for finding the minimum values of these quantities as the port terminations vary in bounded rectangles in the complex plane. This provides a numerically efficient way to assess the impact of variability in the port terminations to the system performance. As an example, we investigate the impact of imperfect impedance matching to the performance of a biotelemetry system composed of magnetically coupled small loops.