A Compact 19.7-to 43.8-GHz Power Amplifier With 20.3-dBm Pₛₐₜ and 35.5% PAE in 28-nm Bulk CMOS

This article presents a broadband millimeter-wave (mm-wave) linear power amplifier (PA) to support 5G and beyond wireless communication. An asynchronously tuned coupled resonator (ATCR) circuit model is introduced to effectively design PA's non-ideal transformer-based broadband output matching network (OMN). Two adaptive feedback linearizers (AFLs) and multi-gated transistor (MGTR) techniques are adapted to optimize the linearity. Both amplitude-to-amplitude (AM <tex-math notation="LaTeX">$-$</tex-math> AM) and amplitude-to-phase modulation (AM <tex-math notation="LaTeX">$-$</tex-math> PM) distortion are improved over one octave with these techniques. A prototype PA is implemented in 28-nm bulk CMOS to verify the proposed ideas. The measured PA realizes 76% <tex-math notation="LaTeX">S₂₁</tex-math> <tex-math notation="LaTeX">$-$</tex-math> 3-dB fraction bandwidth (FBW) from 19.7 to 43.8 GHz, fully supporting five operating bands in 5G new radio (NR) frequency range 2 (FR2), i.e., <tex-math notation="LaTeX">n</tex-math> 257– <tex-math notation="LaTeX">n</tex-math> 261. The measured <tex-math notation="LaTeX"></tex-math> AM <tex-math notation="LaTeX">$-$</tex-math> PM <tex-math notation="LaTeX"></tex-math> is less than 4 <tex-math notation="LaTeX">∘</tex-math> over 24 <tex-math notation="LaTeX">$-$</tex-math> 43 GHz. The large-signal measurement results show that the PA realizes 18.7 <tex-math notation="LaTeX">$-$</tex-math> 20.3-dBm <tex-math notation="LaTeX">Pₛₐₜ</tex-math> , 16.8 <tex-math notation="LaTeX">$-$</tex-math> 19-dBm OP <tex-math notation="LaTeX">1dB</tex-math> , 24.9% <tex-math notation="LaTeX">$-$</tex-math> 35.5% PAE <tex-math notation="LaTeX">ₘₐₓ</tex-math> , and 20.6%–29.7% PAE <tex-math notation="LaTeX">P1dB</tex-math> over 22 <tex-math notation="LaTeX">$-$</tex-math> 40 GHz. For 5G NR FR2 200-MHz 64-QAM signals 9.7-dB peak-to-average power ratio (PAPR), the PA achieves an average <tex-math notation="LaTeX">Pₒᵤₜ</tex-math> /PAE of 11.0 dBm/8.7% with <tex-math notation="LaTeX">$-$</tex-math> 25.2-dB EVM <tex-math notation="LaTeX">ᵣₘₛ</tex-math> at 24 GHz. The proposed PA achieves a compact size with a core area of 0.088 mm <tex-math notation="LaTeX">²</tex-math> , making it very suitable for large-scale phased array beamformers.