Cree Speeds Development of GaN Doherty Ampliﬁers with AWR's Microwave Office
Cree Inc., a major force in the development of Silicon Carbide (SiC) MESFETs and Gallium Nitride (GaN) HEMTs for RF and microwave wireless applications, relies on AWR's Microwave Office design environment to bring its hybrid-based GaN power amplifiers to fruition. One of the most impressive (and challenging) was the CDPA21480 Doherty amplifier that delivers 480 W peak and 80 W average RF power for WCDMA applications in the 2110 to 2170 MHz UMTS band.
By using Microwave Office, Cree's designers were able to optimize the Doherty's performance over a range of power levels using individual source and load pull measurements for the Doherty's carrier and peaking amplifiers. The design task was aided considerably by the software's simulation accuracy as well as the accuracy of its models, which when complemented by Cree's accurate large-signal models reduced design time by as much as 70%. The amplifier design required the full breadth of Microwave Office software's capabilities, from linear frequency-domain and harmonic balance simulation through electromagnetic (EM) analysis.