SiC MESFET power amplifier for 3.6 GHz - 3.8 GHz WiMAX application

摘要

Silicon-carbide (SiC) devices have received increased attention for high-power, high-speed, high temperature, and radiation-hard applications due to their superior properties, including wide band-gap, high saturated electron velocity, high breakdown electric field strength, and high thermal conductivity. The high breakdown field allows silicon carbide devices to operate at much higher voltages than silicon (Si) or gallium-arsenide (GaAs) devices and to have significant RF output power at high temperatures. The high thermal conductivity implies that silicon carbide has high-power handling capability. This paper describes the two-stage 5 W broadband power amplifiers using a commercially available silicon carbide Metal Semiconductor Field Effect Transistors (MESFETs), Cree CRF-24010F. The frequency range covers 3.6 GHz to 3.8 GHz for using WiMAX base-station application. The 2nd and 3rd order harmonic cancellation technique was introduced to obtain high linearity. A cascade topology was employed to increase isolation and stability throughout the bandwidth. At V{sub}(Ds) = 24 V and I{sub}(Ds) = 840 mA (two stage), 10 ± 1 dB power gain, average 37 dBm (5 W) output power, 24 % power added efficiency have been achieved in the two-stage design. The results are being discussed and compared with simulations.