A novel 2-Dimensional correction method for mm-Wave Cartesian I/Q Modulators

This paper proposes a self-corrected In-phase/Quadrature-phase (I/Q) digital Cartesian modulator. The modulator is comprised of double balanced Gilbert cells to mitigate code dependent input and output impedances. Transistor-level simulations in 28 nm bulk CMOS demonstrate a static error vector magnitude (EVM) of −35 dB at 79 GHz carrier while providing 9.5 dBm peak output power with ~19% drain efficiency. Transistor level analysis shows that the linearity is limited by the transconductance (gm) I and Q input code dependency. To address this dependency a self-contained 2-dimensional correction technique is proposed. The proposed correction method improves the EVM from −35 dB to −42.5 dB without compromising the output power, power efficiency and occupied silicon area. The proposed solution enables linear and power efficient transmitters (TXs) for mm-Wave applications.