Ultrahigh efficiency obtained with GaAs-on-insulator MESFETtechnology

摘要

Significant results of measurement and calculation of power-addednefficiency (PAE) and drain efficiency are presented for MESFET's thatnuse GaAs-on-insulator. Ultrahigh PAE of 89% was obtained at 8 GHz with angain of 9.6 dB using a 3-V supply. When the voltage was increased to 4nV, the peak PAE was 93% at 210 mW/mm with 9.2-dB gain. The idealncurrent-voltage characteristics with practically zero leakage currentnand large transconductance near pinchoff yielded PAE values approachingnthe theoretical limits of overdriven operation. The application ofnconventional assumptions concerning drain efficiency is discussednrelative to devices that approach these theoretical limits. Alsondiscussed are the pitfalls of various figures of merit of efficiencynwhen applied to these devices. Hence, there are two types of technicalnbarriers associated with very-high-efficiency devices: the physicalnrealization and their characterization