Interesting simulation. What is the purpose of the RC marked FET bias? In calculating efficiency, are you using the power available after the generator resistance (not before). If using the generator output power, you're of course, losing half the power in the source termination resistance. In the simulation, with all components ideal, I'd expect the efficiency to be 100%. Harold --=20 FCC Rules Updated Daily at http://www.hallikainen.com Not sent from an iPhone. --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .