U-HF model

Unilateral type model:: that has an input impedance and a fixed output impedance of 50 ohms.

Model with high frequency memory: ie that it considers only the frequency dispersion caused in the operating band of the amplifier; it ignores the dispersion caused by long-term phenomena such as self-biasing or self-heating effects.

Mathematical description.

The general equation of the model is:

with

The extraction process consists of identifying the kernel, then calculating a function of approximation in power (by Splines) and in frequency ("Polynomial function" or "Poles and Residues").

For more details one can consult the references:Accurate RF and microwave system level modeling of wideband nonlinear circuits

Identification principle.

The principle is to record AMAM and AMPM conversion characteristics on the frequency band and the power dynamics considered.

Input quantities :

Output quantities :

Validity domain.

The HPA-U-HF model is the simplest nonlinear amplifier model. Its extraction requires relatively little information about the component, ie one-tone CW measurements, performed on a nominal load impedance. It therefore takes into account only the dispersive effects present in the amplifier band and ignores other memory effects such as those due to polarization or heating.

It is therefore suitable for applications processing signals with quasi-constant envelope (frequency modulation), radar (frequency translation or slow amplitude, low duty cycle). This model does not take into account load impedance changes.