Need diagram of an efficient mixer circuit with discrete BJT transistors

Hello
Can someone give me effecient mixer circuit with discrete BJT transistor(s) that's to be used to generate IF of 10.7MHz of RF signal with about 100MHz?

What's better, to build the LO stand alone? or self excited mixer with LO built in?

If mixer DG in ADS will help me in such design, then please anyone send tutorial for it..

Any comments or addins will be appreciated...
Thanks alot in advance,
Ahmad,