Abstract: The present disclosure relates to semiconductor structures and, more particularly, to a common-gate amplifier circuit and methods of operation. The structure includes at least one well in a substrate, a first metal layer connected to a gate of a transistor circuit, a second metal layer overlapped over the first metal layer to form a capacitor, and a third metal layer connected with vias to the first metal layer and overlapped with the second metal layer to form a second capacitor. At least one capacitance in at least one of a junction between the at least one well and the substrate and between overlapped metal layers of the first metal layer, the second metal layer, and the third metal layer.