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

Research output: Contribution to journalArticleScientificpeer-review


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.

Original languageEnglish
Pages (from-to)1446-1456
Number of pages11
JournalIEEE Journal of Solid-State Circuits
Issue number5
Publication statusPublished - 2022


  • Clocks
  • Computer architecture
  • Current-steering digital-to-analog converter (DAC)
  • Delays
  • digital pre-distortion (DPD)-free
  • digital-intensive transmitter (DTX)
  • direct-digital RF modulator (DDRM)
  • I/Q image
  • IQ-mapping
  • Microprocessors
  • mixing DAC
  • Modulation
  • PA pre-driver
  • Power generation
  • quadrature up-converter
  • Radio frequency
  • radio-frequency digital-analog converter (RFDAC).


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