Group III nitride Doherty amplifier using different epitaxial structures

A Doherty amplifier comprising:

• a main amplifier and a peaking amplifier that are electrically connected to a same input signal source and comprise different epitaxial structures of a Group Ill nitride material, such that:
• the epitaxial structure of the peaking amplifier provides the peaking amplifier with a higher power density than the epitaxial structure of the main amplifier;
• and/or
• the epitaxial structure of the main amplifier provides the main amplifier with a higher gain than the epitaxial structure of the peaking amplifier;
• and/or
• the epitaxial structure of the main amplifier provides the main amplifier with a higher transconductance than the epitaxial structure of the peaking amplifier;
• and/or
• the epitaxial structure of the peaking amplifier enables the peaking amplifier to have a higher maximum current than the epitaxial structure of the main amplifier;
• and/or
• the epitaxial structure of the main amplifier provides the main amplifier with more linear amplification than the epitaxial structure of the peaking amplifier;
• and/or
• the epitaxial structure of the main amplifier and the peaking amplifier comprise different polarities.