Optimising RF linear Amplifier for maximum efficiency and linearity

TL;DR

This paper presents a method to optimize RF LDMOS amplifier efficiency and linearity by adjusting biasing based on the modulation envelope of the input RF signals.

Contribution

It introduces a biasing strategy that adapts to the RF input signal's envelope to enhance amplifier performance.

Findings

Improved efficiency when biasing in compression mode for non-varying envelope signals.

Enhanced linearity when biasing for linear operation with varying envelope signals.

Adaptive biasing method tailored to input signal characteristics.

Abstract

A method for increasing efficiency of radio frequency (RF) amplifier employing laterally diffused metal oxide semiconductor (LDMOS) transistors coupled to an RF exciter depending on the emission mode of modulated RF input signals generated by exciter, if exciter output signal is of a type where modulated RF signals do not have continuously varying envelope, biasing the LDMOS transistor in the RF amplifier with fixed quiescent drain current and fixed drain voltage supply to cause LDMOS transistors to operate in compression and if exciter output signal is of a type where modulated RF signals do have continuously varying envelope, biasing the LDMOS transistors in the RF amplifier for linear operation.