A 290 GHz Low Noise Amplifier Operating above $f_{max}/2$ in 130 nm SiGe Technology for Sub-THz/THz Receivers

This paper presents the design of a low noise amplifier (LNA) operating at center frequency 290 GHz in 130 nm SiGe BiCMOS technology with
$f_{t}/f_{max}$
of 300 GHz/450 GHz. The LNA consists of four stages of pseudo-differential cascode topology. Each stage is tuned and matched at different resonant frequency to obtain broadband frequency response around center frequency. This LNA provides 12.9 dB of gain at center frequency 290 GHz and 11.2 dB at 300 GHz. The 3-dB bandwidth is measured to be 23 GHz and simulated noise figure is 16 dB. The LNA draws 68 mA current from 2V supply. It shows the potential of silicon technologies to operate as high as
$2/3(f_{max})$
with decent gain and linearity at 300 GHz range. To the authors' knowledge, this LNA achieves, without any gain-boosting technique, the highest gain at
$2/3(f_{max})$
in SiGe technology.