Transmitter and Receiver in 0.13 μm SiGe for Gas Spectroscopy at 222–270/444–540 GHz

This paper presents a transmitter (TX) and a receiver (RX) with a cross-polarized bowtie-antenna on a silicon lens for gas spectroscopy at 222–270 GHz and the doubled frequency at 444–540 GHz. TX and RX are fabricated in 0.13 μm SiGe BiCMOS technology. Both use two integrated local oscillators for frequency subbands 222–256 GHz and 250–270 GHz, which allow operating in one branch of the TX and RX at 222–270 GHz and in a second branch of the TX and RX at 444–540 GHz by frequency doubling. The directivity of the cross-polarized bowtie-antenna of the TX and RX is optimized for these two frequency bands with an estimated value of 24.4 dBi at 260 GHz, and 29.5 dBi at 520 GHz. Absorption spectroscopy of gaseous methanol is used as a measure for the performance of the TX and RX in the lower and upper frequency bands.