A 28GHz Beamformer Element Demonstration Using Monolithically Integrated GaN and Si Transistors in 300mm GaN-on-Si Technology

This paper presents the first demonstration of a complete monolithic heterogeneous integrated GaN-Si CMOS system. Using GaN N-MOSHEMT and Si PMOS in 300mm GaN-on-Si technology, a fully integrated 28GHz beamformer is designed and characterized. Both the transmitter and receiver contain phase shifter and variable gain amplifier (VGA). The phase shifter is capable of 360° phase tuning with 36 phase states. The VGA provides 10.4dB gain tuning range with 16 gain steps. In the transmitter path, the beamformer achieves 21.1dBm Psat and 25.3dB gain at 26GHz. In the receiver path, the gain, IP1dB, IIP3, and noise figure are 26.8dB, –22.8dBm, –15.7dBm, and 5.8dB at 28GHz, respectively.