Title :
A packaged 86 W GaN transmitter with SiC varactor-based dynamic load modulation
Author :
Andersson, Christer M. ; Ozen, Mustafa ; Gustafsson, David ; Yamanaka, Keiji ; Kuwata, Eigo ; Otsuka, Hiroyuki ; Nakayama, Makoto ; Hirano, Yoshikuni ; Angelov, Iltcho ; Fager, Christian ; Rorsman, Niklas
Author_Institution :
Microwave Electron. Lab., Chalmers Univ. of Technol., Goteborg, Sweden
Abstract :
Output power scaling based on class-J dynamic load modulation (DLM) theory is used to design an unprecedentedly high power microwave transmitter with varactor-based DLM functionality. Matching networks are realized on high dielectric constant substrates in order to reduce the form factor. The fully matched DLM PA incorporates a 24-mm GaN HEMT powerbar and a stack of four SiC varactors, all fit into a CuW package (40 mm × 20 mm). Peak output power is reconfigurable by changing the drain voltage, while retaining the DLMeffect. Under pulsed conditions at 40 V the PA delivers a peak power of 86 W at 2.14 GHz. Efficiency enhancement by DLM is 10-15 percentage-units at 6 dB output power back-off (OPBO). Employing digital predistortion (DPD) with a vector switched generalized memory polynomial (VS-GMP) the ACLR is -46 dBc at an average output power of 17 W and a drain efficiency of 34%. These results prove the potential for high output power levels in varactor-based DLM transmitters.
Keywords :
high electron mobility transistors; modulation; power amplifiers; radio transmitters; DLM theory; HEMT powerbar; OPBO; class J dynamic load modulation; digital predistortion; drain efficiency; drain voltage; efficiency enhancement; fully matched DLM PA; high dielectric constant substrates; high power microwave transmitter; matching networks; output power backoff; output power scaling; peak output power; power 86 W; varactor based DLM functionality; varactor based DLM transmitters; varactor based dynamic load modulation; vector switched generalized memory polynomial; Microwave theory and techniques; Modulation; Power generation; Substrates; Transistors; Transmitters; Varactors; Gallium nitride; high efficiency; power amplifiers; silicon carbide; varactors;
Conference_Titel :
Microwave Conference (EuMC), 2013 European
Conference_Location :
Nuremberg