A 2-40 GHz PHEMT MMIC Active Balun Frequency Doubler

An ultra-broadband PHEMT MMIC frequency doubler is designed. It comprises a FET active balun stage and a push-pull doubler in common-source configuration. Due to the purely lumped-element concept, the required chip area is very low. Using broadband compensation and matching networks, a nearly flat output power performance up to a limit of 2/3 fT with acceptable conversion loss is predicted in circuit simulations. First measurements on a waveform measurement system confirm the expected principal performance.