The Various Angles of Outphasing PAs: Competitiveness of Outphasing in Efficient Linear PA Applications

The demand for linear and highly efficient RF amplifiers has continued to rise without showing signs of stopping, as the world looks to the implementation of 5G. Modern communication signals gave rise to the demand, as the desire to efficiently utilize the limited electromagnetic spectrum led to widespread use of amplitude- and phase-modulated signals, e.g., LTE and LTE Advanced, that use carrier aggregation to achieve broader bandwidths. The defense industry may provide even more applications, as electronic warfare techniques make use of multitone and sometimes noise-like signals that have statistics similar to communication signals. Radars are required to limit emissions in adjacent bands, but traditional rectangular pulses have high out-of-band emissions. Gaussian pulse shaping can be used to improve spectral efficiency, limiting emissions and sidelobes, while adding amplitude modulation [1].