Below is a bandpass filter which I want to use in a RF circuit and I wanted to design it using the extra element theorem. Below shows my attempt to find the transfer function of the input impedance of the network.
I included the input impedance of the circuit connected at the output of the filter. I don't think my final answer is correct, since this is a 4th order circuit and the denominator of the transfer function is of 3rd degree. All the time constants and gains were calculated when putting the components in their DC state. For the transfer function H(s), Rd was factored out of the denominator and numerator and the limit as Rd went to infinity was taken.
What did I do wrong?
