A 200-260-GHz Voltage-Controlled Distributed Attenuator in 130-nm BiCMOS:C Technology

This work presents a wideband passive variable voltage-controlled attenuator (VVA) to control signal powers in the J -band. The VVA is manufactured in a 130-nm BiCMOS technology with fT/fmax = 300/500 GHz. The design is based on a distributed T-attenuator architecture. The design methodology aimed to achieve a wide bandwidth (BW) across attenuation states while maintaining low minimum insertion loss (IL) in compact silicon area. Hence, a distributed inductor-based approach is followed rather than the series varistors or transmission line architectures. The VVA is capable of handling Pin up to 18 dBm with a compression of 0.5 dB. A minimum IL of 5.5 dB was measured within a 3-dB BW of 60 GHz (200-260 GHz) across 13 dB of the voltage-controlled attenuation range. The core circuit occupies 0.015 mm2 of silicon area. To the best of the authors' knowledge, this is the first presented VVA at this frequency range suiting very well highly linear wideband VGAs for sub-THz transmitters (TXs).