Linearity Of Low Microwave Noise Algan/Gan Hemts

The linearity of low microwave noise AlGaN/GaN HEMTs was evaluated with two-tone excitation measurements at optimum low noise biases. A 0.15 x 100 mum(2) device yields an output third-order intercept point (OIP3) of 23 dBm at V-ds = 3V, and V-gs = -5V, where a noise figure (NF) of 1.0 and 1.75 dB was obtained at 10 and 20 GHz, respectively. The C/IM3, linearity figure-of-merit under the large RF signals, saturates near -28 dBc as V-ds becomes greater than the knee voltage. Both applied bias and gate periphery dependence of the linearity were evaluated. Realisation of highly linear low-noise GaN HEMTs is feasible.