Reflection-less matching VS Complex conjugate matching

[ykykouai]

Hi, I am learning the transmission line theory. I found that there are two impedence match: Complex conjugate matching and Reflection-less matching.
As I know the aim of Complex conjugate matching is used for maximum power transfer. sometime, the two impedence matching can not be achieved at the same time.
But I wonder what the meaning of reflection-less matching is? and when to apply complex conjugate matching ? and when to apply reflection-less matcing?

Thanks

 

[biff44]

in linear systems, they are the same thing. To get the minimum reflection coefficient, you cancel out the reactive part of the load impedance, then match the remaining resistive part to the 50 ohms test impedance.


It only gets cloudy in things like a power amplifier, where you really do not have an output impedance to even test until it is loaded properly (large signal S parameters). And in a power amp, the match at the harmonics makes a difference too.

Another cloudy case is a lownoise amplifier front end, where you deliberately mismatch the input impedance to operate at the region of minimum noise figure.