| Autor: |
Matsubara, H., Ishihara, K., Miyadai, N., Nojima, T. |
| Předmět: |
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| Zdroj: |
IET Microwaves, Antennas & Propagation (Institution of Engineering & Technology); Dec2008, Vol. 2 Issue 8, p813-822, 10p, 4 Diagrams, 2 Charts, 10 Graphs |
| Abstrakt: |
A new circuit construction technique that actively utilises second harmonics injection (HI) to realise fifth-order predistortion (PD) for power amplifiers (PAs) with memoryless AM/AM and AM/PM conversions is proposed. Applying a combination of the proposed technique and cuber predistortion (CPD) to third-order distortion yields the simultaneous compensation of both third- and fifth-order intermodulation distortion (IM3 and IM5); capabilities are not possible with the conventional third-order PD approach. Since the proposed method can be implemented as a simple analogue circuit, it betters compactness and lowers cost. In order to derive the PA bias condition at which second HI works most effectively, a complex power series nonlinear model that allows both amplitude and phase nonlinearities to be dealt with simultaneously is used. To confirm the author's compensation theory, a 2 GHz band PA and a hybrid lineariser that employs second HI and CPD are fabricated and experiments are performed. About a 20 dB simultaneous reduction in IM3 and IM5 is achieved with the two-tone test. A W-CDMA one-carrier test is also conducted to verify the improvement in adjacent channel leakage power ratio compared with CPD only. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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