A new linearization technique for MOSFET RF amplifier using multiple gatedtransistors

A simple linearization technique using multiple gated common source transis tors is proposed where gate width and gate drive (V-gs - V-th) Of each tran sistor are chosen to compensate for the nonlinear characteristics of the ma in transistor. To demonstrate the feasibility of this approach, a prototype double-gated RF amplifier using two MOSFETs is implemented and its RF char acteristics are compared with those of a single one. The results show that, compared with a conventional single-gate transistor amplifier, the third o rder intermodulation (IMD3) is improved by 6 dB with similar gain, fundamen tal output power, and de power consumption. Because the auxiliary transisto r is smaller than the main one and biased at subthreshold, adding this does not affect amplifier characteristics appreciably other than the nonlineari ty. With further optimization using multiple gated transistors, much better nonlinear performance per power consumption would be expected.