Linearity of Millimeter-Wave Graded-Channel GaN HEMTs under Quadrature
Amplitude Modulations
Abstract
We report large-signal linearity and power-added-efficiency of
high-speed graded-channel GaN-based HEMTs at 30 GHz under 64-QAM and
256-QAM at 6V or less operations. These graded-channel GaN HEMTs show
the fT of 160 GHz and exhibit a peak power-added-efficiency of 55% at
30 GHz. Under the 64-QAM and 256-QAM, the error-vector-magnitude (EVM)
of less than 5 % was measured at the average output power of 16 dBm,
about 3 dB backed off from the saturated output power.
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