A Doherty amplifier, comprising: a metal baseplate having a die attach region and a peripheral region; a main amplifier and one or more peaking amplifiers, wherein each amplifier comprises a transistor die attached to the die attach region, each transistor die including at least one RF terminal facing away from the baseplate; a multilayer circuit board comprising: a first side attached to the peripheral region; a second side facing away from the baseplate; a first embedded electrically conductive layer that is separated from the second side by a first embedded composite fiber layer; a second embedded electrically conductive layer that is separated from the first side by a second embedded composite fiber layer; and an embedded dielectric layer that is disposed between the first and second embedded electrically conductive layers (144, 146), and that has a higher dielectric constant than either of the first and second embedded composite fiber layers (144, 146); an RF impedance matching network that is electrically connected to an RF terminal of at least one of the amplifier transistor dies, and that comprises one or more reactive components (C1, L1) formed from at least one of the embedded electrically conductive layers. a metal baseplate having a die attach region and a peripheral region; a main amplifier and one or more peaking amplifiers, wherein each amplifier comprises a transistor die attached to the die attach region, each transistor die including at least one RF terminal facing away from the baseplate; a multilayer circuit board comprising: a first side attached to the peripheral region; a second side facing away from the baseplate; a first embedded electrically conductive layer that is separated from the second side by a first embedded composite fiber layer; a second embedded electrically conductive layer that is separated from the first side by a second embedded composite fiber layer; and an embedded dielectric layer that is disposed between the first and second embedded electrically conductive layers (144, 146), and that has a higher dielectric constant than either of the first and second embedded composite fiber layers (144, 146); an RF impedance matching network that is electrically connected to an RF terminal of at least one of the amplifier transistor dies, and that comprises one or more reactive components (C1, L1) formed from at least one of the embedded electrically conductive layers. a first side attached to the peripheral region; a second side facing away from the baseplate; a first embedded electrically conductive layer that is separated from the second side by a first embedded composite fiber layer; a second embedded electrically conductive layer that is separated from the first side by a second embedded composite fiber layer; and an embedded dielectric layer that is disposed between the first and second embedded electrically conductive layers (144, 146), and that has a higher dielectric constant than either of the first and second embedded composite fiber layers (144, 146); an RF impedance matching network that is electrically connected to an RF terminal of at least one of the amplifier transistor dies, and that comprises one or more reactive components (C1, L1) formed from at least one of the embedded electrically conductive layers.