Study on Large-signal Linearity and Efficiency of AlGaN/GaN MODFETs

Linearity and efficiency of AlGaN/GaN MODFETs were investigated under large-signal conditions. The power-added-efficiency (PAE) of 0.25×200 ¿m2 devices was found to be ~33% and ¿45% without and with harmonic tuning. Third-order Intermodulation (IMD3) was also measured using the two-tone technique. Third-order Intercept Point (IP3) of ~ 29 dBm at Pin=15 dBm was obtained at f0=5 GHz (¿f= 10 MHz). Load-pull contours showed that the impedance values for best PAE and Pout are very close. IP3 was found to be insensitive to the gate bias voltage. In addition, high efficiency and high linearity can be achieved simultaneously with the assistance of harmonic termination.