Rf Linearity Study Of Sigehbts For Low Power Rfic Design, Part Ii-Analysis

An analysis is introduced for the third-order-intermodulation (IM3) cancellation induced by the emitter-terminations, which has been observed in part I of this paper. The analysis shows that the IM3 can be perfectly cancelled if the emitter impedance at the second harmonic and the sub-harmomc frequencies are terminated properly and if the effect from q(bc) is negligible. When the effect of q(bc) can not be neglected, optimized source and load. harmonic terminations are proposed to minimize the q(bc) effects. Increasing the source. impedance at the fundamental frequency is found effective in minimizing the residual IM3 that is not cancelled from the proposed terminations.