Predistortion linearization to 100 GHz

The need for the transmission of information at ever greater data rates has moved the need for linear power amplifiers (PAs) to the millimeter-wave (MW) bands. This paper discusses progress in advancing the state of the art of PA linearization to above 100 GHz. The use of analog predistortion (PD) at MW is discussed, and the characteristics of an E/W-band linearizer described. Measured performance of the predistortor, and simulation results with a modeled TWTA are shown. The linearized TWTA is predicted to achieve an AM/PM of <; 2°/dB, and at 3 dB output power backoff (OPBO) with a 16QAM signal, a spectral regrowth of > 30 dB with an EVM of <;2%. The PD characteristics (adjustable increasing gain, and both positive and negative phase change) needed to correct both TWTAs and SSPAs were achieved up to 100 GHz. This unit is believed to be the highest frequency linearizer ever produced.