Speaking of reflection, enjunear, my mind doesn't click on one thing. According to Pozar and the following figure from his Microwave Engineering textbook, the input matching network is placed to convert the source impedance Z0 into Zs, which is Zin conjugate (Zin*), such that Gamma s is the conjugate of Gamma in, and maximum power transfer can be realized. However, by doing so, the interface between the source impedance Z0 and the input impedance looking into the input matching network will not be matched. Hence there will be severe reflection happen at this interface. Why don't we change our strategy and make the input matching network such as Zin is converted to Z0 so that there is no reflection at Z0 and input matching network junction? Basically, there are two choices for input matching, one is to match Z0 to Zin*, another is to match Zin to Z0. Why do people prefer the first choice?