Abstract
This paper discusses the linearity of a class-E X-band PA in a digital polar transmitter. The PA is nonlinear since it is compressed by 2.2 dB when achieving a 59% PAE at 10 GHz. Load-pull is performed under a two-tone test and the resulting optimal efficiency impedance is found to be over 30% different from the single-tone load-pull. In addition standard two-tone load-pull measurements indicate that the impedance for max P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">out</sub> coincide with worst nonlinearity (IMD). Surprisingly, in the two-tone polar load-pull, impedance for max P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">out</sub> differs significantly from the impedance corresponding to worst IMD. Therefore, under polar modulation a different matching circuit should be designed for optimal linearity and efficiency. The PA is part of a digital polar transmitter which enables linearization including phase predistortion, with IMD levels over 11 dB lower than in the standard two-tone test. Load-pull performed on the polar class-E PA shows that the level of intermodulation products varies for different signals input into the PA.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
