The post appears to have generated some interest. Specifically, how does the
match/mis-match, as the case may be, affect one of the (perhaps the) most
important paramater which is the input 3rd order intermodulation distortion
level? And what about loss?

In other words, will a mixer (not limited to diode mixers) operate equally
well into any termination as long as it is R+j0?

AL