Simple and minimally invasive methods and systems for sensing and computing load impedance

A method for direct load impedance determination for a two-port network comprising:

• connecting the two-port network between a first port and a second port;
• determining component values for an equivalent PI network that models a linear two-port response of the two-port network, the equivalent PI network comprising a first equivalent network element in communication with the first port and having a first admittance to ground, a second equivalent network element in communication with the second port and having a second admittance to ground, and a third equivalent network element connected between the first port and the second port and having a third admittance;
• connecting a linear passive load to the second port of the two-port network;
• measuring a first voltage at the first port and a second voltage at the second port;
• and
• determining a load impedance of the linear passive load based on a relationship of the load impedance to the first voltage, the second voltage, the first admittance, the second admittance, and the third admittance.