A Wideband IQ-Mapping Direct-Digital RF Modulator for 5G Transmitters

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Publication Year
2022
Language
English
Copyright
© 2022 Y. Shen, R.J. Bootsman, S.M. Alavi, L.C.N. de Vreede
Research Group
Electronics
Issue number
5
Volume number
57
Pages (from-to)
1446-1456
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Abstract

This article presents a wideband 2× 12 -bit direct-digital RF modulator (DDRM) operating in a 0.5-to-3-GHz band for 5G transmitters. The proposed digital Cartesian modulator features an advanced IQ-mapping technique to boost RF power by 3 dB and suppress the I/Q image. To verify the proposed concept, a 40-nm CMOS prototype is implemented whose RF peak output power at 2 GHz is more than 14 dBm. It achieves an adjacent-channel leakage ratio (ACLR) of -52 dBc and an error vector magnitude (EVM) of -40 dB for a 20-MHz 256-QAM signal at 2.4 GHz. With a 320-MHz 256-QAM signal, the measured ACLR and EVM performances are better than -43 dBc and -32 dB at 2.4 GHz, respectively, without using any digital pre-distortion.