Ultracompact Inverted Input Delay Doherty Power Amplifier with a Novel Power Divider for 5G mm-Wave

This paper reports on the design of a Doherty power amplifier (DPA) for 5G mm-wave applications. Conversely to standard DPAs, this design presents a delay at the input of the carrier amplifier, which enhances the isolation of the peaking amplifier while the DPA is in its low power regime. Moreover, the circuit leverages a novel power divider (PD) to reduce both size and number of passive components. Moreover, the PD transforms the input impedance of the carrier and the peaking amplifiers to 50 Ω avoiding lossy matching networks. Performance consists of a peak gain without pre-driver amplifiers of more than 7 dB at 26.5 GHz, a back-off efficiency plateau of 5 dB, and a saturation power of more than 14 dBm. The circuit has been fabricated in the IHP 130-nm SiGe technology and occupies an effective area of 660×360 µm
²
, which makes it suitable to be integrated into a beamformer chip.