Direct-Conversion I-Q Transmitter Front-End for 180 GHz with 80 GHz Bandwidth in 130 nm SiGe

This work presents an integrated mm-wave transmitter front-end with independent in-phase and quadrature paths for carrier frequencies around 180 GHz. The up-conversion units consist of a double-balanced active mixer with baseband (IF) buffer, local oscillator (LO) driver and RF power amplifier (PA). A passive 90° hybrid generates the quadrature LO signal and a power combiner joins the PA outputs. The IF-to-RF conversion gain is 10 dB, with an RF bandwidth of 80 GHz. The design supports binary and higher order modulation schemes and exhibits an IF input referred 1-dB compression point of −11 dBm. The saturated output power is 3.5 dBm per path and an LO level of −5 dBm is sufficient for an optimal operation. The total power consumption is 151 mW per path. The final chip occupies an area of 1.4 mm
²
and is fabricated in a 130 nm SiGe BiCMOS process with a maximum oscillation frequency of 450 GHz. The main application of this circuit is ultra-wideband short-range communication with data rates beyond 100 Gbit/s.