Ka-band power amplifier with series connected GaAs IMPATT diodes

In order to improve the performance of mm-wave IMPATT diode amplifiers, the series diode connection has been effectively used. Series connection of diodes at AC and their parallel connection at DC have been realized in a two-diode balance circuit. The amplifier circuit minimizes losses and overcomes impedance restriction of millimeter wave IMPATTs. The practical amplifier possessed near 100% combining efficiency at 36 GHz and had about 0.9 W output power at 15% power added efficiency.