Phase Predistortion of a Class-D Outphasing RF Amplifier in 90 nm CMOS
2011 (English)In: IEEE Transactions on Circuits and Systems - II - Express Briefs, ISSN 1549-7747, Vol. 58, no 10, 642-646 p.Article in journal (Refereed) Published
This brief presents a behavioral model structure and a model-based phase-only predistortion method that are suitable for outphasing RF amplifiers. The predistortion method is based on a model of the amplifier with a constant gain factor and phase rotation for each outphasing signal, and a predistorter with phase rotation only. The method has been used for enhanced data rates for GSM evolution (EDGE) and wideband code-division multiple-access (WCDMA) signals applied to a Class-D outphasing RF amplifier with an on-chip transformer used for power combining in 90-nm CMOS. The measured peak power at 2 GHz was +10.3 dBm with a drain efficiency and power-added efficiency of 39% and 33%, respectively. For an EDGE 8 phase-shift-keying (8-PSK) signal with a phase error of 3 degrees between the two input outphasing signals, the measured power at 400 kHz offset was -65.9 dB with predistortion, compared with -53.5 dB without predistortion. For a WCDMA signal with the same phase error between the input signals, the measured adjacent channel leakage ratio at 5-MHz offset was -50.2 dBc with predistortion, compared with -38.0 dBc without predistortion.
Place, publisher, year, edition, pages
2011. Vol. 58, no 10, 642-646 p.
Amplifier, Complementary metal-oxide-semiconductor (CMOS), Linearization, Outphasing
IdentifiersURN: urn:nbn:se:liu:diva-71781DOI: 10.1109/TCSII.2011.2164149ISI: 000296009700006OAI: oai:DiVA.org:liu-71781DiVA: diva2:453945
FunderSwedish Foundation for Strategic Research Swedish Research CouncileLLIIT - The Linköping‐Lund Initiative on IT and Mobile Communications