GaN Doherty MMIC Power Amplifiers for Satellite Ka-band Downlink

Watt-Level Ka-Band Integrated Doherty Power Amplifiers: Technologies and Power Combination Strategies Invited Paper

“…Several power combination strategies for MMIC DPAs have been tested in [25][26][27], adopting the D01GH GaN-Si HEMT process provided by OMMIC. The considered possibilities for combining power on-chip, which cover most of the solutions typically adopted except for the distributed PA and its derivatives [28], are the following: combination of devices in parallel (current summing), stacking of devices (voltage summing), combination of PAs in parallel (current summing).…”

“…A DPA cell based on the largest transistor available for the selected process is presented in [26]. It has been realized with the aim of testing the effectiveness of an on-chip power combination at the DPA level.…”

“…The combined DPA was then designed, manufactured and is currently under characterization. Preliminary results are presented in [25], where it is referred to as MMIC2. As shown in Figure 2, this is a three-stage architecture, where an additional driver stage is inserted at the input, in front of the two-parallel combined DPA cells.…”

“…The device-level power combination is also explored in [25], with the same technology and performance target, with MMIC1. It is a single DPA with main and auxiliary branches composed of two parallel-combined devices in the final stage.…”

“…The achievable power lowers somewhat when wideband operation is desired, since maintaining the load modulation over wide frequency ranges often calls for sub-optimal loading conditions at saturation. Several power combination strategies for MMIC DPAs have been tested in [25][26][27],…”