A Wideband Analog Predistortion Power Amplifier With Multi-Branch Nonlinear Path for Memory-Effect Compensation

A wideband, multi-branch analog predistorter (MBAPD) is reported to compensate for memory effects as well as memoryless nonlinearity of the power amplifier (PA) for repeater systems with wideband modulated signals. For verification, the MBAPD with three-branch nonlinear path is implemented with a 30 W class-AB PA and tested using a two-carrier wideband code division multiple access (WCDMA) signal with 15 MHz tone spacing at 2.14 GHz. From the measured results at an average output power of 33 dBm, the proposed MBAPD shows the adjacent channel leakage ratios (ACLRs) at plusmn15 MHz offset of -60.4 dBc and -60.2 dBc, which are an improvement of over 25 dB and 12 dB, compared to the PAs without APD and with conventional APD, respectively.