Multimode differential amplifier biasing system

Circuitry comprising:

• a differential power amplifier including a first differential input terminal, a second differential input terminal, a first differential output terminal, and a second differential output terminal;
• an input transformer including a first winding coupled between a single-ended input terminal and ground and a second winding coupled between a first transforming output terminal and a second transforming output terminal;
• a first coupling capacitor coupled between the first transforming output terminal and the first differential input terminal;
• and
• a second coupling capacitor coupled between the second transforming output terminal and the second differential input terminal, wherein the first coupling capacitor and the second coupling capacitor are configured to resonate with the second winding of the input transformer about a predetermined frequency range in order to pass signals about the predetermined frequency range to the differential power amplifier and attenuate signals outside of the predetermined frequency range.