A 0.2-19GHz Zero-IF Reconfigurable Quadrature Transmitter With T-Coil Matching Network

This brief presents a 0.2-19GHz ultra-wideband reconfigurable transmitter in 28nm CMOS process. This brief is based on the analysis of the T-coil matching network, which defines the design boundaries for achieving wideband gain flatness in T-coil voltage transfer. The T-coil with capacitive and resistive loads is applied separately in the matching networks of the mixer and power amplifier (PA), enabling the proposed transmitter to achieve wideband frequency coverage. To achieve the image rejection ratio (IRR) across a wideband, two structures of divide-by-2 circuits are utilized to generate low phase error quadrature LO signals. Driven by the feedforward compensation transconductance amplifier (OTA), the analog baseband low pass filter(LPF) achieves a wide reconfigurable bandwidth(BW) and gain range. The proposed transmitter achieves 8.1-13.4dBm saturation output power(Psat) in a compact area of 1.08mm ${\times }1.92$ mm(2.07mm2). The measured IRR and LO leakage suppression are better than 41dBc/38dBc. The baseband LPF BW is configurable from 100 to 500MHz and gain adjustment range is 20dB in 1.5dB step.