A Pair of 170~250 GHz Up-Converter Mixer with Enhanced Psat and Down-Converter Mixer with Broad IF Bandwidth

Paper in proceeding, 2026

This paper presents a pair of 170∼250 GHz up- and down-converter mixers. The up-converter mixer is designed with enhanced Psat and the down- converter mixer is optimized with a broad IF bandwidth. The up-converter mixer is designed based on the fundamentally pumped Gilbert cell with
a differential pair of common-base transistors stacked on top. The down-converter mixer is also modified from the Gilbert cell topology, while the IF outputs are DC-coupled through an optimized emitter-follower stage for a broad IF bandwidth. Both up- and down-converter mixers are designed with the IQ-balanced configuration and fabricated in Infineon’s 90 nm SiGe BiCMOS technology. At an IF frequency of 4 GHz, the up-converter mixer shows a measured conversion gain of around 15 dB over 170∼250 GHz and a typical Psat is +1 dBm. The down-converter mixer covers a similar RF-bandwidth of around 170∼250 GHz with a maximum conversion gain of 0 dB. At an LO frequency of 245 GHz, an IF bandwidth of 22 GHz is obtained.