A high-frequency device includes a metal base, a dielectric substrate mounted on the metal base, an insulator layer provided on the metal base, covering the dielectric substrate, and having a dielectric constant smaller than that of the dielectric substrate, and a first line that overlaps the dielectric substrate as seen from a thickness direction of the insulator layer and is provided on an upper surface of the insulator layer to form a first microstrip line.

Example embodiments relate to Doherty amplifiers. One example includes a radiofrequency (RF) power amplifier. The RF power amplifier includes an input lead. The RF power amplifier also includes a first output lead. Additionally, the RF power amplifier includes a first semiconductor die arranged in between the input lead and the first output lead. The first semiconductor die includes a first edge arranged adjacent to the input lead and an opposing second edge arranged adjacent to the first output lead. Further, the RF power amplifier includes a field-effect transistor integrated on the first semiconductor die. The field-effect transistor includes a gate bondpad assembly and a drain bondpad assembly. The field-effect transistor also includes a plurality of gate bondwires and a plurality of drain bondwires. In addition, the field-effect transistor includes a plurality of gate fingers extending in a first direction and a plurality of drain fingers extending in a second direction.