Enhanced linearity of AlGaN/GaN HEMTs via dual-gate configuration for RF amplifier applications

This study investigates RF linearity performance of a GaN dual-gate HEMT, focusing on its two-tone intermodulation characteristics. The dual-gate configuration is implemented to enhance linearity performance by reducing feedback capacitance to 41.8 fF/mm, achieving a reduction of 73 % when compared to conventional single-gate HEMTs. The dual-gate device showcases a small-signal gain of 23.5 dB at 2.1 GHz, which remains constant regardless of DC gate bias voltage V-B. Intermodulation distortion could be mitigated by increasing V-B, as evidenced by device's highest OIP3 of 30.1 dBm at V-B of 3 V and a drain voltage of 20 V. Additionally, the OIP3/P-DC reaches a peak value of 10.6 dB at V-DS of 5 V. A comparison between the dual-gate HEMT and a conventional single-gate device demonstrates a 3.7 dB gain increase of and a linearity improvement of 5.9 dB. These results highlight the advantageous power gain and high linearity of the dual-gate structure, indicating its considerable potential for RF amplifier applications that require minimum signal distortion.