Investigation of Various Envelope Complexity Linearity under Modulated Stimulus Using a New Envelope Formulation Approach

Abstract

In [1] a new formulation for quantifying the linearizing baseband voltage signal, injected at the output bias port, to linearize a device behaviour was introduced. A key feature of this approach is that since it is formulated in the envelope domain the number of linearization coefficient required is independent of the envelope shape, complexity. This property is validated by performing baseband linearization investigations on a 10W Cree GaN HEMT device. Modulated signals with increasing complexity 3, 5, and 9-tone modulated stimulus, at 1.5dB of compression, were utilized. In all cases just two-linearization coefficients needed to be determined in order to compute the output baseband signal envelope necessary. Intermodulation distortion was reduced to around -50dBc, a value very close to the dynamic range limit of the measurement system.