Next Generation Ultra-linear Super High Frequency/Extremely High Frequency (SHF/EHF) Solid State Power Amplifiers

Future military satellite communication systems will achieve higher signal capacities by employing complex modulation and channel schemes that are closely spaced in frequency. Nonlinearities in the terminal electronics, particularly power amplifiers, cause spectral regrowth in the adjacent channels and degradation of error vector magnitude (EVM). This effort is to develop an approach for an ultra-linear 44GHz amplifier. The amplifier linearity should support an adjacent channel power ratio of -40dBc for a typical quadrature phase shift key modulation at output power greater than 1 watt with power added efficiency of greater than 30%.                  Our proposed approach is to achieve this goal by developing a linearized 44GHz amplifier using envelope tracking. This technology is being developed at Auriga as a powerful linearization technique for high crest factor signals, but has never been reported at this frequency band. The experiments proposed for Phase I will provide the amplifier parameters necessary to meet the power and efficiency goals.  Using these parameters, we will address the optimum device selection and amplifier design approach in the later part of Phase I.                   At the end of Phase I, we will have completed the following tasks:  1) Design a linearization amplifier system, 2) Project performance of linearized amplifier under QPSK drive, 3) Demonstrate highly efficient amplifier design approach and 4) Select the necessary device (type, size, bias conditions, etc). BENEFIT: High efficiency linear amplifier technology at 44 GHz will enable high data rate communication via satellites. The technology will be applied to ground terminals which will be able to send and receive high speed data, critical for both military and commercial applications. The technology developed here can also be applied to other frequencies in the Ku to Q bands, which include various terrestrial communication applications.