Impedance+Matching

__ **Impedance Matching** __

If one recalls the Maximum Power Transfer Theorem, one will remember that maximum power transfer occurs in when the load and source impedances are matched. In between every block in the cascade of amplifiers and filters on the RF board, there is an impedance matching block designed to keep the overall system input and output impedance at 50 Ohms within the bandwidth of interest, thus minimizing power losses in the path that would be due to impedance mismatch. These impedance matching networks typically take the form of either low-pass of high-pass LC filters. They were designed by generating the theoretical s-parameters of the system output at the end of each successive stage, and matching the load to 50 Ohms (since the input impedance that each integrated circuit in the design wants to see is 50 Ohms) using smith charts.