Broadband RF‐predistortion supporting carrier aggregation

Abstract

In this work, a frequency reconfigurable broadband radio frequency-predistorter (BB RF-PD) is proposed that can effectively suppress the power amplifier (PA) intermodulation distortion from 200 MHz to 2.5 GHz. It is an attractive lineariser solution for radio repeaters in long distance communication, where baseband information is not readily available. For broadband signals, existing linearisation techniques become intractable due to high cost and power consumption. The proposed BB RF-PD eliminates the use of data converters, field programmable gate arrays, but still provides the well-intentioned linearisation using the passive components. Three application scenarios have been investigated – (i) and (ii) intra-band: 160 MHz long-term evolution (LTE) signal and 100 MHz two-tone signal, and (iii) inter-/multi-band: two-component carrier LTE signal with frequency spacing of 1 GHz. For verification, the proposed BB RF-PD is implemented with a 10 W HMC8500 PA and tested using 160 MHz signal at 1.8 GHz. It delivers an adjacent channel power ratio (ACPR) of −45.65 dBc with an improvement of 16.87 dB, while for inter-band scenario a new technique has been devised for multiband communication, which is known as BB multipath RF-predistorter. It delivers an ACPR of −50 and −47 dBc for lower and upper CC, respectively.