A new diode-based curve-fitting predistortion lineariser for GaN power amplifier |
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| Authors: | Muhammad Taher Abuelma’atti Abdullah MT Abuelma'atti TK Yeung |
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| Affiliation: | 1. Department of Electrical Engineering , King Fahd University of Petroleum and Minerals , Box 203, Dhahran 31261 , Saudi Arabia mtaher@kfupm.edu.sa;3. COMDEV Europe Ltd. Triangle Business Park , Aylesbury , HP22 5SX , UK |
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| Abstract: | In this article, a new strategy is presented for selecting the breakpoints on a typical characteristic of a lineariser for a saturating nonlinear amplifier. As a proof of concept, using this strategy, a new Schottky-diode based curve-fitting predistortion lineariser for a 1.65?GHz centre frequency, 50?MHz bandwidth, 30?W GaN power amplifier is developed. The proposed lineariser is tested using the two-tone test and the Quadrature Phase-Shift Keying (QPSK) modulated signal. The results show that a 3?dB improvement in the overall gain of the linearised amplifier is achieved. Moreover, for output power levels up to 36?dBm, the linearised power amplifier provides better rejection of the third-order intermodulation. Because of the hard nonlinearity of the GaN power amplifier at the high end, this improvement in intermodulation rejection vanishes for output power levels around 41?dBm. |
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| Keywords: | amplifiers analogue circuits intermodulation linearisation power amplifiers |
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