A Novel Sub-6-GHz and 28-GHz GaN Switchable Diplexer MMIC for Carrier Aggregation with Massive MIMO Full Duplex Link

This paper presents a novel sub-6-GHz and 28-GHz GaN switchable diplexer microwave monolithic integrated circuit (MMIC) for carrier aggregation (CA) with massive multiple-input multiple-output (MIMO) full-duplex (FD) link, which can mitigate self-interference (SI) in CA operation and can select antenna. The switchable diplexer MMIC is successfully demonstrated by 0.25-μm GaN foundry process to ensure the high power handling capability in front-ends (FEs). The developed GaN switchable diplexer MMIC indicates the insertion losses of less than 2.0 dB and 2.5 dB at 3.7 GHz and 4.5 GHz, respectively, with the isolation of more than 21.3 dB at 28.5 GHz. For another bias state, the isolations of more than 31.9 dB and 28.3 dB at 3.7 GHz and 4.5 GHz, respectively, with the insertion loss of 3.0 dB at 28.5 GHz are obtained. A developed GaN sub-6-GHz and 28-GHz switchable diplexer MMIC contributes to highspeed techniques such as CA with massive MIMO FD link for 5G and beyond 5G applications.