Since the first demonstration of GaN transistor in 1993  GaN HEMTs have emerged as the most powerful and the most power efficient solid state RF sources for 1 GHz - 110 GHz frequency bands. For cellular base stations GaN power amplifiers (PAs) are already eroding market share of LDMOS, particularly for frequency bands exceeding 3 GHz. The growing market for GaN PA is also reducing the cost of GaN components. Due to the their superior combination of power and efficiency, GaN MMIC’s are now poised to capture a large share of base station and wireless backhaul market for proposed millimeter-wave 5G frequency bands (24 GHz, 28 GHz, 39 GHz, and 66-76 GHz, 81-86 GHz,…). In addition, the most recent generation of highly scaled GaN HEMT’s is likely to make significant inroads into mmW 5G mobile handset market. These highly scaled GaN HEMT have already demonstrated, on a MMIC level, power added efficiency PAE of 59% at a frequency of 32 GHz  and Noise Figure (NF) of 1 dB at a frequency of 37 GHz . The PAE of 59% is 15% point higher than the next best PAE reported for a Ka-band MMIC, while the NF of 1 dB matches the lowest noise figure reported for a Ka-band LNA. These highly scaled MMIC’s can be powered by a lithium ion phone battery with minimal power regulation or conversion, as their optimum peak PAE bias voltage is in 2 V to 4 V range [3,4]. Highly scaled GaN MMIC are, hence, excellent components for mmW 5G mobile handsets, because they can greatly extend the battery lifetime, due to exceptional combination of very high PAE, very low NF and of the optimum operating bias voltage that matches the voltage of a typical cell phone battery. This workshop presentation will describe broad overview of millimeter-wave GaN HFET device and MMIC technology, provide a brief history of development of GaN HFET technology, describe the latest advances in development of GaN MMIC power amplifiers for mmW (27 GHz – 170 GHz) frequency bands and discuss process maturity and cost.
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