Wideband D-Band Front-end Transmitter Components in a 90-nm SiGe Process

This paper characterizes two front-end components for a wideband D-band transmitter (TX). First, a three-stage, differential common-emitter (CE) power amplifier (PA) with cross-coupled capacitors offers high gain, unconditional stability, and wideband inter-stage transformers that result in more than 30 GHz of 3-dB power-gain bandwidth. Second, a 2-bit vector-modulated phase shifter (PS) uses one-hot encoding to reduce the number of high-speed control lines per TX channel and ease scaling to large multi-channel arrays. The PA and PS are designed in a 90-nm SiGe HBT process with f<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</inf> = 375GHz. The PA reaches a saturated output power of 13.6 dBm with 10.2% power added efficiency (PAE). The phase shifter has an input 1-dB gain compression point (IP1dB) of -4.8 dBm at 135 GHz with root-mean-square (RMS) gain and phase error of 0.7-2.0 dB and 6.1-14.2<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">o</sup> across 115-155 GHz, respectively.