A 2 to 18 GHz Compact High-Gain and High-Power GaN Amplifier

The design and implementation of a high-gain and high-power, efficient and broadband monolithic microwave integrated circuit (MMIC) power amplifier (PA) using a 0.1-μm GaN HEMT process is presented. For the first time, triple-stacked GaN transistors is used in a non-uniform distributed amplifier to achieve high power and high efficiency simultaneously. Further, a similar stacked transistors cell with feedback technique is adopted as a compact driver amplifier to enhance the broadband gain performance. Measured results of the MMIC PA across the 2 to 18 GHz band show at least 29 ± 1 dB small-signal gain, an output power of 9.1 to 15.8 W and an average power add efficiency greater than 25%. The chip occupies a die area of 2 × 3.5 mm 2 . To the best of the authors' knowledge, this work reports the first PA which covers the frequency range of 2 to 18 GHz and achieves the combination of highest gain, about 10 W output power, together with the smallest die size among all published single chip GaN PAs to date.